5.0GL-B stumbling and stalling before hitting plane

[ddbyrd3]

I have a 2002 Glastron GX205 with a 5.0GL-B that starts fine, runs great, until i beach her for about an hour or so. When we push off, she fires up just fine, and as I idle out of a cove she runs great, however, when i throttle up to pull the boat onto plane, she stumbles and at times stalls. After about a minute or so of cranking her and adding throttle, she will fire back up and run great all day, until I beach her again, then she does the same thing after sitting. She has a new fuel pump, this issue happens with both the new and old fuel pump, I installed a new Edelbrock 4 barrel, she also did this with the factory 2 barrel, new cap, rotor, Taylor wires, NGK plugs, and when she runs I have 5 PSI of fuel pressure.

Any ideas as to what I may need to address???? This weekend, i replaced the main fuel line from the tank to the fuel pump, and i blew out the vent tube to make sure there was no blockage, and I made sure the floats were set correctly.. I have not tested it since making those changes.

Could I be chasing an electrical issue??? The one thing I have not verified is the fuel pressure when this occurs. Possible vapor lock??

 

[SD2600]

Verify your fuel pressure... u can rent a pressure guage from a local auto part store just ensure u have the correct fitting

 

[ddbyrd3]

I have a fuel pressure gauge on the fuel rail. It is a consistent 5 PSI.

 

[ddbyrd3]

So I am going to replace the ignition Control Module. And the coil, just because. The module, i believe may be the cause. After extensive research on failure modes, the ignition module can be a result. I will post back after swap them out.

 

[Misterbulbous]

I have had the exact same problem with my 2002 Horizon 190 (5.0 GL-B) for about 10 years. Google and others will describe it as vapor lock - which is plausible. Normally, I can get the engine re-started after a few minutes of cranking, but this summer I had a situation where I had to call a tow boat after 45 minutes (naturally it started just as the tow boat got there). Just like yo u said, mine will start fine, idle out a little and then when I go to get on plane it bogs down and dies. After eventually restarting it never repeats until the next extended downtime.

For my situation, I've noticed that the engine compartment tends to get very hot - especially when boating in 100° Tennessee weather - so, I've taken a step to insulate my fuel line, which hasn't helped. Others have recommended an insulative spacer between the carburetor and intake manifold, which I haven't tried. Regarding diagnostics, I've mostly looked at superficial stuff like fuel filter, gas condition (sea foam made worse), and clean spark arrestor. My next step is to verify fuel pressure.

The challenging aspect for me is that the engine runs like a dream other than this issue of stalling out after sitting for an hour.

I plan on borrowing a fuel pressure gage tonight just for fun.

 

[ddbyrd3]

So I will encourage you to look up ignition module failures, and you will see that a module that is going bad has the same issues we are having. They require dialectic grease on the back of them, if they overheat, regardless of engine compartment temp, they will cause the motor to stall and not refire for a period of time.

My brother in law had the same issue, different boat, it was fual injected, yes, yes, I know they are night and day different, bottom line is he replaced his ECU and his boat is as good as new.

I will be replacing my ignition module this weekend.

 

[ddbyrd3]

My problem has been resolved..

when I removed my old ignition module there was no more thermal grease under it, may have been the reason it was going bad.

went to Napa Auto Parts, bought a new module, took my boat out today for 6 hours, not a single stalling issue..

so happy!!!!!

 

[Misterbulbous]

My problem has been resolved..

when I removed my old ignition module there was no more thermal grease under it, may have been the reason it was going bad.

went to Napa Auto Parts, bought a new module, took my boat out today for 6 hours, not a single stalling issue..

so happy!!!!!

Your issue must be pretty repeatable if you were able to confirm after 6 hours. Mine is pretty sporadic, but not a bad idea to look at the ignition module - as you have suggested.

 

[ddbyrd3]

I was chasing this issue for several seasons. It didn't happen all the time, but it happened enough. 3 times I beached the boat, after about an hour or so, leaving the cove trying to get on plane. is when it would stumble, and at times stall.
It didn't happen at all last time out. I'll be taking the boat out again this weekend and I will report back after that trip if the issue occurs or not.

 

[Misterbulbous]

^ yeah. Definitely curious to see if it's a permanent fix for you.

 

[ddbyrd3]

As you stated in your post, everything pointed to a vapor lock issue. I insulated ALL my fuel lines, fuel pump, everything, and still had the symptoms. Even added the carb spacer and it didn't help, although it did add some top end speed. I never lost fuel pressure either.

 

[ddbyrd3]

I know this post is 3 years old. UPDATE: I took my boat out quite a few times since I reported the issue had been resolved, with no issues, well until last weekend. Under moderate, but consistent throttle, it would cough, after sitting at the beach for a couple hours, it once again stalled while getting on plane. I pulled the carb and cleaned out the passages with carb cleaner & compressed air. Next I will pull my ign module and check the thermal grease. I will report back... This is a frustrating issue to have nearly every season.