5.7 Merc Stalls at 800 RPMs

[Stingray2000240cs]

Hello Everyone,

First of all this is my first boat so I'm a little new to he marine engine world in general. My Stingray 240CS starts everytime with no problems. It idles at around 500 RPMs. I have noticed that I may have a stuck Thermostat. Water seems to discharge from the engine immediately. I guess and hope this could be my problem, but I just wasn't sure if this would cause my engine to stall. After I let the engine warm up to around 160F I start easing the throttle up slowly, and it always fails at around the same RPMs. Do you guys think this could be due to the stuck thermostat? Could it be the throttle interrupt switch? Does anyone know at what RPMs the interrupt switch does it's thing? I just winterized the boat so I won't be able to test, but I appreciate any feedback.

I have the Bravo 3 outdrive.

Thanks!
Jeremy

 

[Don S]

Re: 5.7 Merc Stalls at 800 RPMs

Welcome to iboats Jeremy. We are going to need more information on your engine.

http://forums.iboats.com/showthread.php?t=220416

 

[tpenfield]

Re: 5.7 Merc Stalls at 800 RPMs

Hello Everyone,

Do you guys think this could be due to the stuck thermostat? Could it be the throttle interrupt switch? Does anyone know at what RPMs the interrupt switch does it's thing?

I have the Bravo 3 outdrive.

Thanks!
Jeremy

No thermostat would not do that trick. Your engine will put water out through the exhaust elbows even when the thermaost is closed, so no worries there.

I would be more apt to look at the shifter/throttle controls for the problem since it is stalling at a certain RPM and one that is getting to be above idle speed.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

My apologies Don. I should have noticed that thread. Here you go. Thanks.

1. Motor ID# OL635851 (5.7L EFI)
2. Outdrive is Merc Bravo 3

Tpenfield, the thermostat is actually stuck open I think. I could be wrong. As soon as I start the engine with earmuffs on, the engine starts releasing water out of back at the base of the gimble housing (hope that is the right terminology).

 

[Don S]

Re: 5.7 Merc Stalls at 800 RPMs

The thermostat does not control the amount of water coming out of the boat, only what circulates through the engine. Water always come out the transom shield and prop area after running through the manifolds. That's what keeps the rubber hoses in the exhaust from burning up.
If you are running only 160? max, you may need a new stat, but I really doubt that's your problem.

Here is a link you can download the OEM service manual from, http://www.4shared.com/document/Pss92fbC/Service_Manual_24.html

You are also going to need a Diagnostic scanner similar to this http://www.rinda.com/marine/mtspec.htm#techmate , a DVM (and know how to use it) fuel pressure gauge for EFI systems and maybe a few other things.

 

[Bondo]

Re: 5.7 Merc Stalls at 800 RPMs

Water seems to discharge from the engine immediately.

Ayuh,... As it Should, unless the block, 'n manifolds have been drained...
Water has to be flowing 100% of the time it's runnin'...
The T-stat only controls whether it's expelling hot, or cold water...
But it's always expelling water...

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

Thanks for the education on the Thermostat. I guess that makes perfect sense. I was told that if water is coming out then the thermostat is open so i didn't think to question it. Thank you very much for the manual Don! I guess I'll start reading and see what I can come up with. I'll go ahead and order the code scanner too. If anyone else has any other suggestions, feel free to fire away.

Thanks,
Jeremy

 

[Don S]

Re: 5.7 Merc Stalls at 800 RPMs

Do you keep up with maintenance items? Fuel filters, tuneups, etc?

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

I just bought the boat last week so I havent done anything yet. I was planning on new wires and plugs, new impeller, and fuel filter.

 

[maicoman]

Re: 5.7 Merc Stalls at 800 RPMs

Check for movement at your shift cable on the top of your exhaust manifold.If it is kinked and is not moving the shift cable the shift interrupt will kill the motor.Disconnect the shift cable and or take the 2 wire connector to the shift interrupt switch and jump a wire between the connector going to the computer.Make sure you have the throttle in nuetral and you will then be able to rev the motor if the cable is your problem,or your switch for that matter.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

That sounds like great troubleshooting information Maicoman! I really appreciate it. I think I understand what your saying. I'll have to take a look at it to make sure.

 

[r.j.dawg]

Re: 5.7 Merc Stalls at 800 RPMs

No shift interrupt switch on Bravo drives. They are used on Pre-Alpha, Alpha One and Alpha Gen II drives. Seeing as your engine is an EFI I would try to get my hands on a scan tool to check for codes. I'm betting you have a bad IAC or TPS.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

wow, I didn't know that RJdawg! I'ver ordered a Techmate so I hope that works. My buddy has a car scanner that says it can be used on boats too, but I haven't looked at it or know the name of it.

 

[r.j.dawg]

Re: 5.7 Merc Stalls at 800 RPMs

Scan tools are a great tool, but sometimes they fail and you have to go by your gut. For example, this summer, my 350 Mag EFI/MP would stall when shifted into gear. A scan told me the IAC was at fault. I replaced it and the boat ran fine for about 15 minutes. It would idle but as soon as I gave it a little throttle it would stall. Another scan came up with nothing but a dock mate suggested the TPS could be faulty. I changed it and it has run like a champ ever since. Always trust your gut.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

My gut is telling me its the TPS. I only paid 9k but i wasn't able to put the boat on the water because of some timing issues. I know thats not smart but after meeting the guy and his family my gut told me to trust him. Plus i have about 3400 in receipts for an engine rebuild the boat went through in july. The boat was last on the water in september and i just got it last week. I hope i got a good deal i love the boat. It seems like a much more expensive boat.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

I just spoke with the marine shop that did all the engine work back in July and a lot more was done to the boat than I could see on the receipts (some of the line items only have part numbers). The guy said that mechanically everything was gone through and that I shouldn't need to do anything to the boat. He felt like the engine should be as good as new (or better in his words). One thing I liked to hear was that he did replace the gimbal bearing and did an alignment. I'm glad to hear that becuase I was going to pull the outdrive off tonight and do an inspection. He wasn't sure why it was stalling without seeing it.

 

[Stingray2000240cs]

Re: 5.7 Merc Stalls at 800 RPMs

So, after all the worrying and reading troubleshooting threads all over the internet I put my boat on the water for the first time. I cant tell you why but the boat ran perfect! I couldnt have imagined it running any better. I'm not sure it didt run right on earmuffs but I'm not complaining. Thanks for all the help and information!

 

[r.j.dawg]

Re: 5.7 Merc Stalls at 800 RPMs

Good to hear everything worked out for you Jeremy. Enjoy your boat.