Holley 4160 Issues

[csuggs]

I've been chasing a carburetor flooding problem now for several weeks with no real good news to share. We rebuilt the carb with the correct Holley kit from skidim (rebuild done by an "old school hot-rod junky"). But even after the rebuild, I'm having issues. Here's the scenario - when we put the boat in and firts start it up, it starts fine, and runs great for as long as you want. I can even shut it down momentarily and it will start right back up. The problem comes when I shut it down hot for a longer period of time. The bilge reaks of fuel and the motor floods . . big time. After I finally get it running, it runs like crap because the plugs are fouled.
We have made adjustments to the idle mixture screws and float settings in an effort to resolve the problem but so far no luck. Then today I decided to start from the beginning. I removed both fuel bowls an set the floats according specs given to me by skidim and others on this forum. Then I ran the motor in my driveway. It ran really good as usual and started every time. When we were finished I decided to wash the boat and while I was drying it I noticed a strong fuel smell from the bilge area. I opened the motor cover and the engine was really hot, and what's more the carburetor was just as hot as any other part on the motor - just acting like a giant heatsink. And there was evidence of fuel getting into the throat of the carb.
Our conclusion is that the heat must be causing the fuel to expand enough to allow it to flow or "boil" over the bowl. This would explain why every time I have made a test run (without the engine cover attached) it has never flooded. Then when I think everything is good, I put the engine cover back on, take the family out and after the first time I shut it down for any length of time it floods again.

Now here's my question . . . without re-inventing the wheel so to speak, what can I do to keep the motor cool when shut down? I'd rather not have to raise the engine cover everytime I want to stop. Also, is it possible that the 10% ethanol fuel I've been using will expand or "boil" over at a lower temp than straight gas? I wonder if running straight gasoline (if I can find some) will resolve the problem.

[rludtke]

My boat behaved this way when the impellor was wearing out. The engine temp on the gauge was fine, but the exhaust would burn bare skin. The radiant heat from the exhaust elevated the under cowl temps to the point that it cause vapor lock issues. Your problem sounds simular, less the vapor lock. I replaced my impellor, and the exhaust riser temps dropped way down. Now they are only warm to touch.

Yes, I would expect the expanding fuel to escape out the float vent, which on the 4160, has J tubes that direct the vent into the carb throttle bores. This is one of the purposes of the vent.
I would not expect fuel to find its way into your bilge, the 4160 marine carburator is designed to not do this. All escaping fuel must be captured, and is by the J tubes. All other oppertunity for fuel leaking is removed (such as the externally adjustable floats, the 4160 doesn't have them).

Also, the expanding fuel should not be able to leak past the float valve, if the float valve is working properly. If fuel is dripping out of the atomizer discharger (in the throttle bore), then your needle is damaged and leaking, or it is being held open by foriegn object. Nothing else will cause a carburator to flood like this.

I suggest you change your raw water impellor to reduce the heat, and inspect the flooding bowl for debri. Remove the debri, and the problem should go away. Also replace the needle and seat to make sure they are not damaged and leaking. Rule the damage and the debri out, and you shouldn't have any more issues, providing the floats are assembled correctly.

Cheers,

[Sunapee Sunsport]

What temp thermostate are you running? What is your engine temp peaking and staying at when you are under way?
I run the 143 degree termostate and my temp stays right at or alittle below 160 degrees.

[csuggs]

Ran the motor on the trailer yesterday. I used a laser thermometer to check some temps and here's what I found:
With motor running, warmed up - carb bowl 98*, coil 108*
Motor shut down, after 45min - carb bowl 141*, coil 136*

With the floats re-adjusted there was no fuel dripping in the carb after shutdown and the motor re-started every time after 1 pump on the throttle lever. We'll have to see what happens the next trip to the river.

Will install a new rwp impeller tomorrow just to be sure. Thinking about installing a hatch of some sort on the top of the motor box to open after shutdown for cooling, maybe even a louvered hatch that would draw hot air out while underway.

[craigfee]

I had the same issue on my 87 Comp. I rebuilt the carb but still had gas dripping after I shut off the boat. I had to acutally keep adjusting the front bowl float and finally fixed the dripping setting the float at 15/32's.

[cadunkle]

Engines get hot after shutdown, your car gets hotter than your boat after shutdown and starts fine after sitting for a bit and going through heat soak. If you want your carb to stay cooler get a phenolic (plastic) spacer to isolate the heat.

[csuggs]

Engines get hot after shutdown, your car gets hotter than your boat after shutdown and starts fine after sitting for a bit and going through heat soak. If you want your carb to stay cooler get a phenolic (plastic) spacer to isolate the heat.

good point

[rludtke]

Engines get hot after shutdown, your car gets hotter than your boat after shutdown and starts fine after sitting for a bit and going through heat soak. If you want your carb to stay cooler get a phenolic (plastic) spacer to isolate the heat.

I should have mentioned this idea earlier. The previous owner installed a 1 1/2" phenolic isolater on my boat, which I decided to keep. I think this does a lot to reduce carb heating after shut down. It won't prevent radiant heating, but it will reduce convective heating. The spacer is the brown colored object beneath the carb:

https://forum.supraboats.com/picture.php?albumid=4&pictureid=15

With any luck, your new impellor combined with the addition of an isolator could get you there without having to cut up your dog house. Although if you had too, take a look at making your dog house drink holders pop out. They could help ventilate the compartment.

[csuggs]

rludtke - I like the phenolic spacer idea, and no - I don't like the idea of cutting up my engine cover. It was just a thought really. If I add the spacer, what do I do about the fuel line? Do you think it will bend enough to reach?

[Blackntan90]

Great looking engine bay rludke! I personally would not cut up the dog house-doing so could feed a fire(god forbid) with oxygen, if one were to occur. On the other hand, the removeable drink holders could be pulled, and used as a fire port for the extinguisher! I really like the phenolic spacer idea, just have to be sure about clearance issues between flame arrester and doghoouse.

[csuggs]

I wonder if I purchased a 1" phenolic spacer if I could just replace the original cast spacer with the plastic one. The question is then I would not have a vacuum port for the PCV valve unless I was able to drill and tap the plastic spacer and install a hose fitting.

[csuggs]

What temp thermostate are you running? What is your engine temp peaking and staying at when you are under way?
I run the 143 degree termostate and my temp stays right at or alittle below 160 degrees.

I use the 160 thermostat and the gauge indicates between 165-170.

[rludtke]

I wonder if I purchased a 1" phenolic spacer if I could just replace the original cast spacer with the plastic one. The question is then I would not have a vacuum port for the PCV valve unless I was able to drill and tap the plastic spacer and install a hose fitting.

You could add the phenolic spacer on top of the original aluminum one. You would just need to replace the carb hold down studs with longer ones. Perhaps you can find a port some where else for your vaccum source? I don't have the extra aluminum spacer installed. My engine is not using a PCV valve to the best of my memory. Instead the valve cover breather is vented to the fire arrester.

I think that the phenolic will machine just fine. I've cut threads in it before, but I can't attest to how leak proof it will be. So I would be sure to use a good thread sealant.


rludtke - I like the phenolic spacer idea, and no - I don't like the idea of cutting up my engine cover. It was just a thought really. If I add the spacer, what do I do about the fuel line? Do you think it will bend enough to reach?

Yes I do. the fuel line bends can be tweeked enough to allow it to fit. But, I ended up cutting a section of my metal fuel line out to install an in-line fuel filter. I recomend you do the same.

[csuggs]

But, I ended up cutting a section of my metal fuel line out to install an in-line fuel filter. I recomend you do the same.

I have a Fram cartridge style fuel filter installed prior to the fuel pump. Do you have this new filter in addition to one like mine? I change the Fram filter cartridge every season, maybe I need to take it apart and see if somethings not assembled correctly.

http://i887.photobucket.com/albums/ac71/csuggs/DSC03157.jpg

[rludtke]

I have a fuel/water separator located in the same location. It looks a little different from yours, but it is the spin-on canister type filter. I suspect that your filter is also a fuel/water separator. If so, it will not adequately filter the small stuff. You want on the order of a 5 micron filter.

Because the in-line filter is probably less than $15, I recomend you add it anyway.

I did my wheel bearings and changed the oil yesterday, and put my boat on my friends dock where it will spend the next few days. This was my first oppertunity to get the boat wet this year, as it has been so cold and rainy this spring. I noticed that my right side valve cover does have a PCV valve, and that it sources it's vaccum from a port on the manifold, not the carb spacer. If you can find an an alternate vaccum source, you could swap the aluminim spacer for the phenolic.

[csuggs]

There is a plugged port on the intake that looks like it could be vacuum. I'll check it out.

I went out this afternoon and the boat ran great until we got back to within 10 ft of the ramp. The motor stalled and flooded.

[rludtke]

I went out this afternoon and the boat ran great until we got back to within 10 ft of the ramp. The motor stalled and flooded.

Sounds a lot like the problems I was having. Intermitant issues can be very frustrating to figure out.

I would find a tiny sliver of what I suspect was a rubber hose fragment sitting in the inlet chamber of the float bowl casting near the seat. I believe it would float in the fuel, then be drawn into the seat by the flowing fuel, and ultimatley hold the needle open causing extra rich mix, and dripping discharge nozzles. Then after shut down, the piece would float away, and the problem would disapeer for a while, only to start again when the piece of rubber found its way into the seat, etc etc.

Its only a theory, but getting rid of the rubber hose fragments sloved the problem.

[csuggs]

I'm going to take the carb back apart today, clean thoroughly and install an inline filter. Then we will see what happens.

[jeffreyk573]

Rick,
Could you show a picture of this inline 5micron filter. That sounds like a really good idea. Also, what brand and where did you get it.

[rludtke]

My boat is on my friends dock right now, so it may be a day or two before I can take a picture. But I will post one soon.

In the mean time, I'll try to describe the installation a bit better.

For starters, the filter is a metal can about 3" long x 1 1/2" in diameter, and features a 3/8" (I think, but don't quote me) hose nipple on each end. Mine will have a NAPA part number that I will supply later. The folks at NAPA will be able to select the correct filter for you if you know the outside diameter of the metal fuel line that runs from the pump to the carb, and the size of your engine (351 Ford). I think it is a 3/8" inside diameter fuel line, but I am not positive. If you are unsure, remove the fuel line and take it into the store with you.

The installation is simple enough: cut out a section of the fuel line a little longer than the length of the filter (on the order of 4" perhaps) with a tube cutter (if you don't have one, pick one up at NAPA or hardware store, or cut it with a hack saw. If you hack saw, be sure to rinse away all of the metal shavings). It is important to determine an appropriate place to locate the filter. The fuel line runs through a couple of tight areas, where the filter would not fit. I found the the roomiest spot to be a few inches above the pump. The filter will come with two correctly sized hose segments and two hose clamps. The filter has a dedicated inlet and outlet, which will be identified with a flow direction arrow. Loosely assemble from the bottom up (lower tube segment to pump, add the filter, add the upper fuel tube segment to the filter, then connect the tube to the carberator), then tighten all connections.

Run the engine on the hose to confirm that there are no fuel leaks and with any luck the problem will not re-occur. The drive the lake may shake more crud loose from the carberator. In my experience, I had to clean out the carberator bowl one more time, because I somehow failed to get all of the crap out of the system. Take some tools with you to the lake, as you might have to go into the bowl one more time. In my case, the float valve seat was jam packed with stuff. I removed it, blew the crap out from the bottom by mouth, and re-assembled.

After that last "rinse" with the filter in place, I never had another issue. My boat starts nearly instantly when cold, and idles smoothly. Before this fix, it was a little more difficult to start cold, and it took attention to keep running during warm up, even when I didn't think it was flooding (it may have been a little bit).

Happy Independance Day (and to our Canadian friends, I hope your Canada Day was a good one).

[csuggs]

Took the carb apart again today to clean. I removed the needle and sprayed everything - finding no dirt. Not even a speck. I did this on both bowls. I also removed the inlet screen and inspected carefully. Finding no visual problems with the carb, and knowing how good it's running until it floods, I wonder if I have a different problem.
See if this makes sense . . . I replaced the coil this spring because I thought it would be a good idea since I had previously replaced the entire ignition system except for the coil. My old coil worked just fine. Mind you that this problem I'm having now with the carb has been going on ever since day one of this season. What if my root problem is the coil? What if it is failing when it gets too hot and I'm flooding the engine as a result of trying to start it with no spark? Do you guys think it would be worth while to put my old coil back on and see what happens - if I still have it? I suppose a new coil could be "bad" or borderline and only fail when it gets too hot? FYI the last two times I had a problem the motor shut down after a fairly long idle going back to the ramp with little or no air moving across the motor.
What do you guys think?

[rludtke]

Did you look before spraying everything? I was hoping you would find a smoking gun.

Have you tryed making a large decrease in the float setting? If you made a large adjustment decrease, and the problem went away, you would know you are on the right track.

Do you pump the throttle more than once to start the engine? Does the carb drip after pumping and trying to start the engine, or does the carb drip right after engine shutdown when it isn't running so well? I am unsure, but I thought you indicated the latter.

I spent the evening at a lakeside party where my boat supplied the party tunes. To keep the battery charged I would start up and let the engine idle for 20 minutes at a time, several times during the evening and night. I don't think idleing is the problem.

You could check your spark to try and evaluate how strong it is. Of course you could try swapping back to the old coil too. I don't think this is the root cause, but then again, I'm sitting in my office behind a keyboard.

Obvously I am not present to fully understand how you start your boat, but because you mention it, there could be a technique issue. It certainly is possible to flood the carb while trying to start. Because I know my accelerator pump is pretty new, and that it is pumping, I only pump the throttle one time when the engine is cold prior to cranking. I don't pump at all when the engine is warm, unless it fails to start immediatly after initiating the crank. If this is the case, I may start over and pump once prior to the next crank. When I crank, the throttle is set at idle.

Here is an odball idea, but what if your needle and / or seat are incorrect?

[csuggs]

Rick - I appreciate all your attention to this . . . thanks!
1. Starting procedure has always been that when cold we pump the throttle twice then crank. When hot we just crank, unless it does not start at which time we pump once, then crank. This has always worked pretty well.
2. Something that comes to mind is that just after we rebuilt the carb we encountered a "stumble" on the hole shot, so at the recommendation of my carb guy I installed a larger squirter for the accelerator pump. That took care of the stumble, but may be causing issue with flooding at start-up. This was a #32 nozzle, and yesterday I switched it for the original #25 nozzle.
3. Upon shutdown, whenever I have checked I do not see gas dripping from the carburetor jets, or tubes, etc. Nothing, just dry. The longer the boat sits the hotter the entire motor gets, up to about 155*. After it sits, I can typically smell gas under the motor cover and it won't start. I open the cover, take the spark arrestor off and see gas in the carb - then I let it air out and after a long wait it will start. During that time the motor is not only "airing-out" but is cooling. Then when I get it started it runs rough - like the plugs are wet, or maybe the coil malfunctioning.
4. Back to the ignition system. I installed a Pertronix Ignitor electronic ignition about 3 years ago. The instructions told me to wire the coil through the ballast resistor - never had a problem. This spring when I replaced the coil I also wired it through the ballast resistor. When I mentioned this to Vince at skidim (where I purchased the coil) he asked about the ballast resistor. According to him, his supplier said that if a customer has a problem with coil performance, to bypass the ballast resistor. That sounds strange to me because they should be able to say that you need it, or you don't need it.

I'm thinking about running it this week like it is, with the #25 squirter installed. Floats are adjusted according to Holley specs. If/When the motor will not start, I could change out the coil on the water and see if that does the trick. I've just been trying to think of "what has changed" from last year to this year. My boat has always started and ran great so I need to get it back to that standard. The only thing I changed before my first time out this year was the coil and thermostat. When I experienced this problem the first time out this year, I had the carb rebuilt - but the original problem never really went away.

Keeping the faith . . . we will whip this!

Clint

[rludtke]

Hi Clint,

When I experience a stumble on acceleration, I just increase my float level a little bit. Try to determine when the stumble occurs: Before or after the secondaries begin to open? If before, adjust the primary float level, if after, adjust the secondary. The larger accelerator pump might be causing starting problems, by possibly flooding the carb when you use it to prime at start-up. But I think this is self-correcting, the engine just has to crank a little longer to get the air/fuel ratio right for starting.

The flooding after shutdown and heat-up problem is obviously due to excessive engine compartment heat.

This heat could be negatively affecting many things. Maybe the coil is breaking down in the heat. So might be the ballast resistor. I would try removing the ballast resistor from the coil power circuit. I don't think it will hurt anything, and it may help.

The heat is certainly is affecting your carburetor. I am surprised that the fuel leaks out the float valve, and not the vent. Your float valve is not sealing as well as it should. Considering that your float valve assy is nearly new, I can't explain why this is so, but I don't like it. I think the float valve should be capable of sealing out the expanding heated fuel. The fuel should be dripping out the vent J tubes, and not the discharge nozzles. Consider trying a different needle and seat combination. Perhaps revert back to the pre-overhaul set, or buy a new set. This leaking valve will be problematic forever.

I think you need to reduce the engine compartment heat too. Have you replaced your raw water pump impellor? How about the thermostat? These components are cheap and easy, and probably should be replaced every few season, or when symptoms occur (and I think they may be occurring). How hot are your exhaust risers when engine is running under load? I can touch mine for a second or more. But when my impellor wears out, the risers will get hot enough to burn skin immediately. When this occurred, the heat after shut down under the engine cover was affecting my carb too, but in my case it was vapor lock. My flooding problems could occur cold, hot, it didn't matter, but of course my flooding was due to particles in the fuel.

[smoothfootn]

Csuggs
I have been battling flooding issues as well. I was seeing raw fuel dripping from the strbd side primary venturi. I thought it was a float issue so I continually lowered the float level and it never fixed it. I rebuilt the carb to start the season so I thought everything was clean. However, I pulled the carb again yesterday and found that I had one plugged port. If looking down through the barrel, there are two ports toward the bow from the primary venturis. The smaller of the two ports was completely blocked. I missed this the first time I cleaned the carb. I blew it out and remounted everything and the dripping stopped. Now, the only thing I am having trouble with is the carb taking too long to idle down. After cruising, I bring it to idle and it idles @ 1000rpm for about 25 sec before settling down to about 600. Any Ideas about how to fix that?? Thanks

[rludtke]

Rick,
Could you show a picture of this inline 5micron filter. That sounds like a really good idea. Also, what brand and where did you get it.

Here are couple of photos of my installation Jeffrey. I realized after I took a second look, that i cut off the lower end of the hard tube and discarded it. I then replaced the tube fitting in the pump inlet with a hose barb fitting to allow the hose and filter to clamp directly to the pump.

[csuggs]

WoooHooooo!!!!! Problem fixed!!!!!

I went out with two of my sons this morning early and the boat ran great, until it got hot - then it start stumbling and "missing" - especially on the hole shot. So we put the boat back on the trailer, went to church, then lunch. But before we went back out to the river I installed the old coil and voila - she ran as good as ever all day. Ran it hard, shut down and just floated several times - always started right away and never missed a beat! I guess I should have left well enough alone with the coil over the winter (maybe I got a bad one from skidim). My dad always says "son, if it 'aint broke, don't fix it" - guess I should listen to him!
:D

[ngavchris]

Congrats to you....... I know the frustration................. Glad you figured it out.