Engine Stall .... Stumped?

[No_Longer_Active_User]

This thing has a single 4cylinder Merc engine correct?

6 cylinder

 

[No_Longer_Active_User]

That is a crock if the compression is fine, you cannot have bad rings or cylinders and the compression is normal/fine. I would get a second opinion.

Yes I'm going tomorrow to a mechanic that's about an hour away....I hope he has better news for me, my boats been tied up for the past two weeks and I sure don't have an extra 2,000 to rebuild the engine!

 

[Andy S]

That is a crock if the compression is fine, you cannot have bad rings or cylinders and the compression is normal/fine. I would get a second opinion.

Compression checks the integrety of the rings and how well the valves are seating. Good for you in getting a second opinion.

 

[JC6275]

Motors get their compression from the rings, if the compression is good on all cylinders the rings can't be bad...

 

[No_Longer_Active_User]

Does the boat have a fuel/water separator or "fuel filter" that looks like an oil filter? If so that could have too much water/separated ethanol gunk to allow enough fuel to pass. I had this happen on my Stingray 4.3 one time. I actually dumped the filter out into one of my zip lock bags because I was basically stranded and didn't have another filter. Then I disposed of it in an oil container when I got home. Not the ideal thing to do, but you can NOT dump that stuff into the water!

Did you get "pops" or noises while going WOT when it slowed down, or did it just bog down? This was also a sign on mine that it was time to change that filter.

No pops....just seemed to get bogged down before stalling out!

 

[0627Devildog]

@No_Longer_Active_User - I totally feel your pain. . . . Be very picky about who you let work on your engine. Check the reviews, and get local input. Don't want to end up like me, with my Sea-Doo (https://jetboaters.net/threads/help-needed-post-from-yjb-update.1178/#post-16755)

 

[steined]

You did the right thing. It's a fueling issue. I'd bet money on it.

 

[Magic]

7 months is not too terribly old for gas, and the water in the fuel thing thing should have caused problems right off since the water will layer below the fuel and get to the pickup sooner than later, and certainly sooner than the 2.5 hours you ran with no trouble......

I agree that spark plug are a good place to start, but also please check/replace the fuel filters. My instinct tells me that through sitting for 7 months, a bunch of crud may settled on the bottom, and running for 2.5 hours might have been enough time for that crud to make it to the fuel filter(s).....

Like I said its just my instinct based on experience, but its not a bad place to start...

Good Luck and please let us know what the mechanics find!

If the compression check is in spec and even between all 6 cylinders, how the heck can your mechanic diagnose a ring problem?

Compression is maintained by two components, rings and valves. and you really can't determine which has failed until you tear it down. There are separate symptoms for each, but not absolute enough to rule out the other....

Something smells fishy here Laura...remember my post above? If your compression is good and even, think fuel, spark and/or timing.

Does anyone know a good SS/Mercury mechanic in or around Ft. Pierce Florida? Better Luck with your second opinion!!

This ain't over yet @No_Longer_Active_User , and we have your back!

 

[Gym]

If the compression check is in spec and even between all 6 cylinders, how the heck can your mechanic diagnose a ring problem?

Compression is maintained by two components, rings and valves. and you really can't determine which has failed until you tear it down. There are separate symptoms for each, but not absolute enough to rule out the other....

Something smells fishy here Laura...remember my post above? If your compression is good and even, think fuel, spark and/or timing.

Does anyone know a good SS/Mercury mechanic in or around Ft. Pierce Florida? Better Luck with your second opinion!!

This ain't over yet @No_Longer_Active_User , and we have your back!

Actually...You can tell which component is bad. If you do a compression check on a cylinder and it's low you squirt a little oil in the spark plug hole and do another compression check. If the compression improves appreciably the problem is rings. If there is no improvement the problem is valves.

If the mechanic said your compression is good on all cylinders your rings and valves have to be good. Is it possible he said four cylinders are good and two are bad? In any event you are doing the correct thing by getting another opinion. You could actually bring this to any local garage mechanic for a compression test. They wouldn't repair your boat but they could certainly check the compression which could confirm or deny the first diagnosis. Keep us in the loop @No_Longer_Active_User

 

[0627Devildog]

Is it possible to diagnose by scoping the motor?

 

[Lspeedss]

I vote fuel issue. Filter or carb...pinched line maybe. Not a compression issue. Not smoking or using oil is it?

 

[4x15mph]

Can you call the mechanic that you probably paid and get his explanation around how the compression checks out okay while he reports that a couple of rings and cylinders are bad? Post back the detail while getting a second opinion.

 

[jcyamaharider]

I vote fuel issue. Filter or carb...pinched line maybe. Not a compression issue. Not smoking or using oil is it?

Actually for his sake I hope it is smoking.....these are 2 stroke motors. So no valves on these motors unless it has power valves. The piston rings are the only thing that will keep compression.

My vote is fuel issue as well.

 

[Lspeedss]

My bad.. I was thinking it was a four stroke...

 

[jcyamaharider]

Yep I figured that. So with it being a 2 stroke it actually makes this issue more simple. As long as each cylinder has equal compression and the compression doesn't have drop, all cylinders are getting oil, fuel, air, and spark, it should fire. Maybe the carbs have some junk in either the idle jets or main jets.....something else to look at.

@No_Longer_Active_User does your boat have a oil reservoir or is it converted over to premix fuel?

 

[spatty99]

I had a 2003 Sugar Sand Tango Extreme with the Mercury 240 hp EFI V-6 2 stroke. If the engines are similar, you should have a fuel/water filter (looks just like an oil filter), as well as a small fuel filter cartridge. Both are extremely easy to change and might help with the issue if fuel related.

 

[JC6275]

@No_Longer_Active_User , just wondering if you heard anything from the second mechanic?? Please keep us posted when you hear something. I for one am very interested in hearing what they tell you this time, as compared to the last mechanic you took it to. I'm sure some of the other respondents are interested as well... Here's hoping for good news for you

 

[0627Devildog]

@No_Longer_Active_User , just wondering if you heard anything from the second mechanic?? Please keep us posted when you hear something. I for one am very interested in hearing what they tell you this time, as compared to the last mechanic you took it to. I'm sure some of the other respondents are interested as well... Here's hoping for good news for you

x2

 

[jcyamaharider]

X3