Can't seem to idle right this spring-1984 Comp

Another year with the 1984 Comp that Michael Hunter restored. Had a good year last year. Not so good this year.

The boat was not very interested in starting coming out of winterization. Took quite a bit of cranking and then quite a bit of warming up before it would finally run at idle on the hose. Stabil was put in a full tank of gas when I winterized in October and fogging oil used on the carb.

I finally thought i had the idle doing well enough so we took it out saturday. Boat would idle ok for a minute and then it would get worse after a couple minutes of idling. I played with the idle air mixture screws throughout the day and never could get it right. Even tried bumping up the idle speed a little. By the end of the day, it idled OK buy soon as you put it in gear would shut off. Boat seemed to run A-OK outside of idle speed.

At this point, I'm thinking i'm probably due for a carb rebuild. I had similar issues to this last year our of winterization but was able to adjust the idle air mixture and it worked out.

Anything else I should check before the carb rebuild? Any good DIYs for said carb rebuild? Planning to order the kit from SkiDim.

Try a new PCV valve

How much old gas is in it. Sounds like bad gas?

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Originally Posted by michael hunter

How much old gas is in it. Sounds like bad gas?

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Full Tank with Stabil from October. Taking it to the shop tomorrow.

I had trouble with the PCV valve bad idle. There only about 5 bucks.

Sounds like a dirty carb. May not really need a rebuild but moreover just a thorough cleaning

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Also in the fall when you lay it up next time, I would advise against fogging the carb and instead fog the cylinders independently. I have never fogged the carb on mine and it fires up every spring on the first attempt every time and idles.

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Originally Posted by Jetlink

Also in the fall when you lay it up next time, I would advise against fogging the carb and instead fog the cylinders independently. I have never fogged the carb on mine and it fires up every spring on the first attempt every time and idles.

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I'm thinking the same thing. I didn't fog the carb the year before and it started up much easier, I'm thinking that the fogging oil probably just gummed it up.

Just got a call from the shop. Sounds like there was a kink the metal fuel line (Probably caused by myself when I tightened it at the carb). They also said the cap and rotor were very corroded and the plugs needed changed. I'll get all that fixed and then I asked them to tune up the carb while they were at it just since i had been messing with it and i'm sure it's not 100% right.

Got the boat back last monday. They replaced the fuel line, new cap and rotor, plugs, adjusted timing. Started it up on the hose in the driveway and it started right up with a smooth idle. Took it to the lake on Friday for a shake down run and it idles well, but is missing as you increase RPM out of idle which it's never done before. Between 3-4000 RPM it's bad enough that you can watch the tach drop a few hundred RPM. Needless to say, it's going back in today as it's never done this before. I'm guessing the timing is off somehow? Not really sure.

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Originally Posted by hoop46

Got the boat back last monday. They replaced the fuel line, new cap and rotor, plugs, adjusted timing. Started it up on the hose in the driveway and it started right up with a smooth idle. Took it to the lake on Friday for a shake down run and it idles well, but is missing as you increase RPM out of idle which it's never done before. Between 3-4000 RPM it's bad enough that you can watch the tach drop a few hundred RPM. Needless to say, it's going back in today as it's never done this before. I'm guessing the timing is off somehow? Not really sure.

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Sound like it could be starving for fuel on the upper end. I rebuilt the carb on my 89' (3) times during the 24 years i owned it. Bought the rebuild kit from Discount Inboard Marine and it always ran great after the rebuild.

So the shop got the fuel line fixed and not leaking and was not able to identify any issues with the missing. So at this point it either was related to the fuel line or is only happening while the engine is in gear. We'll test it out again this weekend.

So I got my boat out of storage last weekend and today I got it all put back together and it fired up on the second crank of the starter after the fuel pump was primed from cranking. It was running good on the hose but had a bit of a stumble off idle which I attribute to bad gas. Topped it off on the way to drop it in the water for the season and added some fuel treatment. Ran like a top by the time I got back to the house and tucked it away in the lift. That is a long way to get to the question of, do you treat your fuel and how full was the tank when you laid it up for the winter? That parts list does sound rather excessive, I think the only thing that they did not throw at it was the kitchen/shop sink.

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Originally Posted by Jetlink

So I got my boat out of storage last weekend and today I got it all put back together and it fired up on the second crank of the starter after the fuel pump was primed from cranking. It was running good on the hose but had a bit of a stumble off idle which I attribute to bad gas. Topped it off on the way to drop it in the water for the season and added some fuel treatment. Ran like a top by the time I got back to the house and tucked it away in the lift. That is a long way to get to the question of, do you treat your fuel and how full was the tank when you laid it up for the winter? That parts list does sound rather excessive, I think the only thing that they did not throw at it was the kitchen/shop sink.

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Jetlink,
I topped it off at the end of the season and treated with sta bil.

As an update, I took it out yesterday and it ran fine for the first half hour or so, then the upper RPM bogging began. Seems to run fine 2500 RPM and below. It began running pretty erraticly after 2500 and it was struggling to get to full throttle. Best way to describe would be that it sounded like it fell down the stairs to get to full throttle, losing and gaining power as it got there and when it got there. Going to start by changing out the fuel filter. Will probably go ahead and drain the tank as well. Anything else?

Fuel filter might be constricting fuel flow but if it can get to full RPM early on before it starts building heat on the block I wonder if the coil is going. I had some run issues I was fighting amongst other issues but long story short, I went new distributor, coil, plugs and wires and obviously adjusted timing with that. Rebuilt the carb a year or two ago and it runs like a top every time now. I do replace the fuel filter in the spring too.

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Originally Posted by Jetlink

Fuel filter might be constricting fuel flow but if it can get to full RPM early on before it starts building heat on the block I wonder if the coil is going. I had some run issues I was fighting amongst other issues but long story short, I went new distributor, coil, plugs and wires and obviously adjusted timing with that. Rebuilt the carb a year or two ago and it runs like a top every time now. I do replace the fuel filter in the spring too.

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any way to test the coil? I haven't replaced the fuel filter since i purchased the boat ~ 3 years ago. I'm sure Michael did at some point when he went through it, but i'd imagine it's due for a replacement.

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Originally Posted by hoop46

any way to test the coil? I haven't replaced the fuel filter since i purchased the boat ~ 3 years ago. I'm sure Michael did at some point when he went through it, but i'd imagine it's due for a replacement.

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So I took my multi meter to the coil. Getting 1.4 minutes ohms from positive to negative And 9,450 from positive to the top. Now I need to find the specs of said coil. Doesn’t have much info on it other than 903

Take a picture of it and post it up here or better yet, ask Mr. Hunter what he had on there. If your issue is not there when you first start up but gradually becomes prevalent with run time and heat build up, I am betting the coil is bad and therefore, testing it while everything is in a sense cold will not reveal a bad coil. I found that out the hard way as I was chasing my tail with what sounds like your problem.

What is the the engine doing? The most common problems are in the carb and the ignition. I forgot what ignition system is in your boat does it have points?

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Originally Posted by michael hunter

What is the the engine doing? The most common problems are in the carb and the ignition. I forgot what ignition system is in your boat does it have points?

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Michael,
Yes it has points. The best way to describe it is a sputter/misfire at high RPMs. Last trip it didn't do this until after about a half hour of running.


I went ahead and ordered a new fuel filter from Skidim on reccomendation from Haugy, as well as a new coil. We'll see how those work.

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Originally Posted by hoop46

I went ahead and ordered a new fuel filter from Skidim on reccomendation from Haugy, as well as a new coil. We'll see how those work.

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Who is this mythical creature you spoke with?

Have you checked the ignition Dwell . I assume the shop you took it to replaced the points and condenser and set the points but maybe not. i have some points in stock you are welcome to I converted all my 351's to HEI ignition.

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Originally Posted by michael hunter

Have you checked the ignition Dwell . I assume the shop you took it to replaced the points and condenser and set the points but maybe not. i have some points in stock you are welcome to I converted all my 351's to HEI ignition.

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They claim to have set the points.

Replace the points or checked them? You should check the dwell [or point gap] sometimes they will slip . Give me a call and I will walk you threw it. 678-227-8833

So i replaced the fuel filter and coil last week and this past weekend the boat performed well. The only hiccup, which i have no explanation of was that it died while going about 30 MPH. Wasn't running rough leading up to that or after, just died. Started it right back up and it ran fine the remaining 15 minute ride back to the dock. At this point we'll just have to see how it goes.

So I haven't had any other issues after running 2-3 more tanks of gas through the boat. I'm thinking a nasty fuel filter was restricting flow.