3.0L mercruiser stalls after 20 minutes

[89SeaRay]

Please Help!!!!

89 Sea Ray with 3.0L Merc starts runs for about 30 minutes then seems to have bad gas and stall, misses and finally bogs all the way down and wont run. After sitting about an hour and turning over many times will start back up. First thought was vapor lock so I put rubber hose and foil over fuel line but it still does it. I have not done anything with the gas the last two winters. The boat is located in Arkansas and I put a can of seafoam in this week and filled it up. checked ceramic filter under fuel pump and also filter going in to carb. Any thoughts suggestions

Thanks

 

[Showtime22]

Re: 3.0L mercruiser stalls after 20 minutes

Any Idea about the age of the fuel pump?

You may want to consider an electric fuel pump if its older. Mine was 45 bucks at Napa. Its a universal pump that puts out 4-6 psi and it makes start up 1 second rather than the 4 seconds my mechanical pump took. Mounting it away from my engine helps prevent vapor lock. May not be the fix though.

Does it always reach a certain temp before stalling? Are the other guages doing anything out of the ordinary?

 

[89SeaRay]

Re: 3.0L mercruiser stalls after 20 minutes

Fuel pump is probally pretty old. I saw some liquid in the sight line? The clear tube that runs from pump to carb. Not much but a little in a valley up by the carb. How hard of an instal is the elec pump. Can it just be mounted on the partition between the motor and battery? Also how do I know what type of pump to get? Is that a Volvo motor? That sounds like a good place to start.

Thanks so much

 

[89SeaRay]

Re: 3.0L mercruiser stalls after 20 minutes

Oh yeah the temp gauge shows 145 and it warms up to that for awhile before it stats bogging down. All other gauges look fine.

Thanks

 

[Bondo]

Re: 3.0L mercruiser stalls after 20 minutes

Fuel pump is probally pretty old. I saw some liquid in the sight line? The clear tube that runs from pump to carb. Not much but a little in a valley up by the carb.

Ayuh,... Replace it with the Right fuel pump...

 

[Showtime22]

Re: 3.0L mercruiser stalls after 20 minutes

The electric pump I got is a Posi-Flo. Its fairly easy to install. It mounted on the side of the engine compartment at a required 45 degree angle. It requires a switched 12 volts. You'll also need some rubber fuel line and some hose clamps. On my Merc I cut the metal fuel line near the carb and hose clamped on.

FOR SAFETY the pump should be run to an oil pressure safety switch. It kills the pump if the engine dies.

 

[capecodder116]

Re: 3.0L mercruiser stalls after 20 minutes

If it were me, I'd read the Adult section item 3 concerning fuel issues first before I go throwing $$$ at something that "might be" the problem....also a simple check would be next time it happens, with the key off go to the carb and manually pump it to see if you've got fuel squirting. If not remove the fitting at the carb fill and get a clear 1 gallon jug and put the end of the fuel line into the jug and have someone turn the motor over to see if your pump is working....

 

[TyeeMan]

Re: 3.0L mercruiser stalls after 20 minutes

Don't forget to check your fuel tank vent and line, make sure they are not plugged tight. If the vent is plugged you wont get any make up air to the fuel tank as you draw fuel out.
I had a Chevy Blazer once that would do kind of the same thing. I swore it wasn't the fuel pump cuz I didn't see any liquid fuel out of the weep hole. BUT it was actually the fuel pump. The arm on the fuel pump was so worn at it's pivot point that it was hardly moving the diaphragm.
New fuel pump and all was well.

 

[89SeaRay]

Re: 3.0L mercruiser stalls after 20 minutes

I also dont think this boat has an fuel water sep. filter in the fuel line. Where would this be located? Fuel line goes to pump and straight to carb. Is this something that needs to be installed? As I said the tank has been left half full two years in a row.

Also new problem the boat wont crank(turn over) very fast at all. It sounds like a dead battery. Had battery tested and said it was good hooked it back up and same thing barely cranks. I felt the starter and it was real hot. Bad starter probally?

Thanks

 

[Showtime22]

Re: 3.0L mercruiser stalls after 20 minutes

There is a fuel/water filter on my Merc 260 that looks like an oil filter before the carb. Its white and round. Yours may have one.

If the engine is barely cranking and you could try turning it over by hand with a socket on the crank end. If it turns over easy it may be the starter. But if it turns over really hard or not at all you could have fuel or water holding the pistons from moving. Remove the plugs and turn it over to blow out the fluid.

Just a thought...

 

[jerryb1]

Re: 3.0L mercruiser stalls after 20 minutes

Also new problem the boat wont crank(turn over) very fast at all. It sounds like a dead battery. Had battery tested and said it was good hooked it back up and same thing barely cranks. I felt the starter and it was real hot. Bad starter probally?

Thanks[/QUOTE]

I have the same problem with my Merc 260. It runs for about 30 minutes, no gauge problems then stalls and will not start. If I let it cool off for 20 minutes it runs again. Let me know if you slove the probelm? I'm suspecting the fuel pump, but am reluctant to spend $130 unless pretty sure.
As far as the starter being hot and cranking slow, it could just be bad connections. Even with new batteries, if the voltage at the starter is 8-9V, it will crank slow and get hot. Put a volt meter after the starter solenoid and see what it is when it cranks. Also the replacement starter solenoids don't last very long, especially the Sierra replacements.

 

[89SeaRay]

Re: 3.0L mercruiser stalls after 20 minutes

Jerry/ Anyone

Did you find a soulution. I didnt same thing this year. I drained complete gas tank last fall. Filled With No Ehtanol gas and added Sta-bil. took out first time today ran great for 30 then started to stall. so reduceded to half throttle and luckly it putted back to ramp. Smelled gas could it be flooding? but why after bout 30 minutes?

We waited 20 minutes it started up and ran fine? ANy help would be appreciated..

 

[tschmidty]

Re: 3.0L mercruiser stalls after 20 minutes

Clogged vent line would be what I would suspect. Disconnect it at the tank and check it.

 

[jerryb1]

Re: 3.0L mercruiser stalls after 20 minutes

Jerry/ Anyone

Did you find a soulution. I didnt same thing this year. I drained complete gas tank last fall. Filled With No Ehtanol gas and added Sta-bil. took out first time today ran great for 30 then started to stall. so reduceded to half throttle and luckly it putted back to ramp. Smelled gas could it be flooding? but why after bout 30 minutes?

We waited 20 minutes it started up and ran fine? ANy help would be appreciated..

Yes i did finally find the solution. I changed the points, condensor and coil and the problem went away. It was not gas related.