Rough Running '88 Saltare

[dbruesehoff]

Hi all,

Another one for ya. So this past weekend I had the boat out on the water, ran great most of the day although it has been running rough to start the season. Starts and idles nice but when under load it struggles and has a heavy engine jolt when cruising through channels and has always struggled to get out of the water. From 1/2 to full throttle it feels like the boat loses power, almost better to run it wide open at 3/4 throttle. When it was running "well" throughout the day I could maybe get 30-35MPH out of it at a little over 4K RPMs. Certainly not as powerful as I thought it should be but it's been like this since I bought it so I haven't questioned much. Late in the day on Saturday I couldn't get the boat to go over 15MPH and wouldn't plane out.

When I got back to the boat launch the boat would barely stay running and would quit when in low RPM cruising speed, even cut out as I went into reverse to slow down loading on the trailer. I got back to the shop last night and pulled the plugs to check compression, all 8 running between 140 and 150 and held strong for at least 30 seconds to a minute. What I did notice through all of this was that #3 cylinder hasn't fired the last 2 outings because I changed plugs at the beginning of the season and the plug in #3 is still new, clearly never fired. So I test plug wires and of course #3 plug wire is bad. Replaced and is now firing. Problem being boat still runs like crap in the driveway with the fake a lake hooked up and the engine jolt when the prop is engaged is still there and rather annoying. The one thing I will say is since that cylinder has never fired it doesn't explain why I lost so much power on Saturday and couldn't get over 15 MPH. Engine temp was 120-140 all day so no over heating causing low power.

I have no idea where to start. I haven't rebuilt the carb yet so I know that is something I need to do. Part of me thinks timing is out in combination with a dirty carb but then still doesn't explain the lower power on the way back to the launch. The rough low speed idle is still got me baffled. Any thoughts on other things I should be checking?

Also, I replaced the flex plate last week and the new one is beefier, but it is noticeably louder than the old, as if there is sand in the tranny. And the engine jolt I am feeling is clearly the reason the old flex plate failed and I am trying to get rid of the issue before it causes the new one go down.

Wondering if I need to drop this off to a mechanic to diagnose the issue and then I can fix from there. Any recommendations on Inboard mechanics in Minneapolis? I would hate to go to a mastercraft or supra dealer but that is looking like it might be my only option.

Here is a link to the flex plate noise, hard to see the engine jolt in this video but it's there.

https://youtu.be/HgfgESYTuyQ

[SquamInboards]

The first thing I would do is to run the engine off a separate fuel tank, like a little portable outboard tank, running a fuel line to the last possible place you could connect a regular fuel hose - probably the pump itself. With a fresh, clean tank of known good fuel, you're eliminating not just one variable, but actually the fuel filter, the fuel lines, the tank, the pickup, and the existing fuel in the boat's tank. If it runs well on that, start working backwards toward the tank. If it runs the same - go forward toward the pump and the carb.

I'd do this before messing with much else.

[middlegriff1]

I agree with Squam on the whole fuel issue. If the fresh "tank" and hose runs well I would replace the hoses, clean the tank and replace fuel water separator. But if not It sounds like the carb needs to be rebuilt. Im not an expert on carbs and know all the ins and outs but it sounds like you first 2 bowls aren't giving much fuel and when you run it 3/4 or wide open, the secondaries are giving you fuel which is why its running better on the high end. If none of that works then take it to a mechanic.

[gnarlydude]

What's your distributor set up? Have you replaced it?


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[dbruesehoff]

Sorry guys, been away from the compute for a couple days. The distributor was replaced with electronic ignition by the original owner. I just bought the boat and am trying to work out the kinks, the boat was very well looked after but pretty sure it hasn't been ran much over the last few years. I am thinking its fuel or electronic, possibly an alternator going bad as I notice I am not pulling 14+ amps while the boat is running, the voltage meter bounces all over the place while running. Carb and fuel could for sure be just another part of the problem, I am planning to replace the fuel lines as I believe they are due and also going to rebuild the carb.

I dropped it at the dealer this morning to see if they could help narrow down the search. Figured it would at least be a good starting point and I also don't have much time to spend working on it during the week as I travel for work so I am on an airplane or in a hotel most of the week. I have been talking to the mechanic at this place for the last few weeks since I bought the boat and he has been very helpful. He's had 2 other boats with the same engine so he has a pretty good base of knowledge, not to mention having worked on inboards for the last 20+ years. Hoping he can steer me in the right direction so I can get this thing back on the water so I can spend my weekends relaxing and not wrenching :)

[dbruesehoff]

Figured I would throw a quick update in on my boat. Dropped it at the dealer a week or so ago. Dealer called a day later to tell me the pinhead who owned it before had #3 and #5 plug wires swapped around. I bought new plug wires and plugs and had him pop all that in while it was there. With the engine in correct firing order, new plugs and new plug wires she runs like a champ. I replaced the prop with an Acme 543 and she is pulling nice and hard all the way up to 40+MPH (air guide speedos).

Now my next issue cropped up now that I have full power lol. When I hammer it out of the hole at full throttle the boat acts like the prop is cavitating, did it with the old prop and now also with the new prop. I am wondering if that could be the wake plate out of adjustment? I can progressively get up and go out of the hole without issue and can hammer it from half throttle while cruising to full throttle and she hauls. Scared the S-H-I-T out of me the first time, thought the trans was slipping and sort of still do although I would think it would do it at different times rather than only coming out of the hole at full throttle. Any thoughts or suggestions?

[chris young]

This feels suspiciously reminiscent of my problem. In my case, the prop was loose, and the key was missing. Once there's force on the prop it seats on the taper. In your case though, since you just replaced the prop and you had the problem before, the next place I'd look is the coupler end just in case it's the same problem at the other end of the shaft. After that, it's probably the tranny. Make sure you check the fluid level exactly per the directions.