Unexplained Power Loss

[Phil Masciantonio]

Hi All,

First time posting here. Appreciate any possible insight.

Over the last two seasons, I have had an unexplainable power loss to the engine. I can only push the boat to about 40% throttle. The boat runs well up to that point, but eventually, there will be a "stutter" in the engine and I have to back down to neutral, sit for a few seconds, and then I can start moving again. It will depend on how much additional weight is on board, but this generally happens around 3.5k rpms with our regular load on board. I will run at 3.5k for a few minutes, and then the stutter begins.

My mechanic and I have tried a few things with no success. Spark plugs were changed, the distributor cap was replaced, and we hooked up an external gas tank to eliminate a gas tank or fuel line issue. The boat is winterized once a year and at that time the oil and filter are changed as well.

Has anyone heard of an issue like this and have any recommendations? Please feel free to ask questions if I didn't provide enough info. Thanks in advance!

 

[Skybolt]

Sounds like a fuel filter issue. There is one on the engine itself that if you connected an external tank, that would use that filter. Could also be a cool fuel problem, the actual pump on the engine.

This may add some insight:

*Gen 3 Cool Fuel Module Issue*

Well, after chasing a fuel problem around for the better part of two weeks, I finally discovered an issue that Mercruiser has known about since 2004 but is in no hurry to discuss. The early model "Gen 3 Cool Fuel Module" that many of us have on our sterndrive Searays has major design issues, and...

www.clubsearay.com

 

[Richard Carlisle]

Had a car do something similar. It turned out to be the electronic ignition module. GM HEI ignition. Sounds like an ignition component is getting hot and breaking down.

if it’s late model, the mechanic should be able to plug in an see what’s going on. Sounds like an ignition component is getting hot and breaking down.

 

[Phil Masciantonio]

Sounds like a fuel filter issue. There is one on the engine itself that if you connected an external tank, that would use that filter. Could also be a cool fuel problem, the actual pump on the engine.

This may add some insight:

http://[URL][URL]http://www.clubsearay.com/index.php?threads/gen-3-cool-fuel-module-issue.51399/

[/URL][/URL]

Thanks for the reply, but if I read correctly, the cool fuel was only on engines built from 04-09, correct? Our boat is a 2016 with the 225hp Mercruiser....

 

[Skybolt]

Thanks for the reply, but if I read correctly, the cool fuel was only on engines built from 04-09, correct? Our boat is a 2016 with the 225hp Mercruiser....

It was more of a general response, I haven't worked on any of the newer gas engines, I have diesels, sorry. But there still is a secondary filter for the injection. That may be clogged as well as the primary one.

@Lazy Daze Dennis may be able to add to this.

 

[Scott215]

You can go a couple of ways on it someone said earlier the ignition module is a possibility and so is the fuel filter or you could have somebody put a scanner on it and see if it's throwing any codes