Everything was fine when I winterized…

[Fish Witch]

Glad you found the problem! But hope what you call the ignition module (sorry, I haven't had a gasser for many years now) isn't the ECM and a lot cheaper. That was a $1k part 15 years ago when a buddy needed one.

[Quickstep192]

Here’s the latest.

The mechanic returned today with additional help knowledgeable in ignition systems.

They went for a run and observed that the problem still existed. They re-verify fuel flow and then replaced the ignition module. Problem went away. They put the original ignition module back and the problem returned. They then put the new module back. Here’s hoping!

[radioman]

Cam worn, issue with lifters.

place I worked at previously had a Chevy van that would bog when you kicked it down into passing gear, after much debate the chevy garage tore down the top end and found a worn cam lobe and 2 bad lifters.

[Deputyrpa]

I wonder if the fuel tank check valves are not working properly. It may run until too much vacuum pressure developes for the pump to overcome at full throttle. Run it off a gas tank as suggested earlier.

[Quik Fix]

Check for restrictions in your exhaust hoses. Varmint nest in winter. Engine is basically an air pump. Air in, air out. If you restrict the flow, it will definitely bog down.

[Quickstep192]

The mechanic has reported that he is officially stumped.

He verified all the fuel paths. Fuel pressure remains constant even when the engine bogs down. The coil isn’t getting hot. Injectors seem to be spraying fuel even when it’s bogging down.

The boat runs OK at first. I’ve run at high rpm’s for probably a half hour before the bogging down starts.


I’m at wits end. It’s prime boating time and I can’t count on my boat to get me home. I’d sure appreciate any guidance. At this point, I’ll entertain decent guesses.

[Quickstep192]

He didn’t say a lot. I think he’s stumped too.

[Quik Fix]

What did the "mechanic" say? You have ruled out a lot of things.

[Quickstep192]

I’m baaaack…

Just had the mechanic over and went for a run.

Motor still bogs down after running at 3800 for a while. It doesn’t happen at first, only after it’s been run if for a little while. Mechanic put a fuel pressure gauge and fuel pressure stayed constant at 35, even when the engine was bugging down. Coil was not hot. Injector spray looked good throughout. Had occasional backfire.

Any thoughts would be very welcome.

[Quickstep192]

This may sound silly, but it probably shows my level of desperation and frustration.

If you were going to take the “Replace Everything” approach, what would you replace?

Off the top of my head, I’m thinking throttle body, fuel cell and coil. What else?

I think those three things would cost $2,500 not counting my labor. I’m pitting this against paying a mechanic $160/hour + travel + mileage + parts to iteratively diagnose the problem. If he’s able to make it out today, it will be his third trip. I get that there can be multiple issues, but I’m approaching the point where I may have as much invested in the mechanic as those three parts would have cost.

One more question - where should I buy a coil, complete throttle body and fuel cell?

[Ship]

Yes. But it will be warm under normal circumstances.

[Quickstep192]

Sorry for the relentless questions, but if you hadn’t already figured it out, I’m above my pay grade on this one.

So, if it’s the coil, it will be noticeably hot to the touch???

[Capjohnson.mike]

Mine did something similar when u bought her. Would run all day on the hose and when i splashed it it would run for 15 minutes then just crap out. Coil would get so hot i couldnt touch it. Fired up and would detonate. my neighbor was convinced it was the carb it but was the distributor and coil.

[Ship]

Jerry, that will tell him if his primary pump is working but with the injection pump, it won't. The pump in the fuel cell. The primary pump should be 5 psi but I have no clue about even testing the fuel cell and beyond.

[Quik Fix]

You can just take your fuel hose and put it in a container while cranking engine. See how much fuel you pump in 10 seconds.