Mercruiser 3.0 litre problems

[trkives]

I have a 1998 stingray with 3.0 litre mercruiser I/O. It starts fine and runs great until you turn it off and try to restart it. Then it will turn over but will not start. This only happens after it is run a while. If I let it run for just a few minutes and then shut it off, it will start again just fine. I had it on the water and ran it for a hour or so and then shut it off and it would not restart. Any ideas? Help please.

 

[dubs283]

Re: Mercruiser 3.0 litre problems

have you inspected the carb immediately after shutting down when warm??

take a look down the throat and see if fuel is running down once you shut it off, if so its time for a re-build

 

[trkives]

Re: Mercruiser 3.0 litre problems

No I have not inspected the carb after shutting it down. I will do that. I do have the choke on the carb locked wide open. I was told that the electric on this motor is a piece of junk and that most folks just leave it wide open.

 

[89mercruiser]

Re: Mercruiser 3.0 litre problems

Sounds like the carb is in need of a rebuild. Had the same symptoms with our 3.0. Had the carb rebuilt and all is good. I've never had any issues with the choke acting up on our 89 3.0

 

[dubs283]

Re: Mercruiser 3.0 litre problems

I was told that the electric on this motor is a piece of junk and that most folks just leave it wide open.

those people probably don't realize that the choke setting is adjustable

 

[trkives]

Re: Mercruiser 3.0 litre problems

I mistypedd before. My boat is a 1989 stingray with the 3.0 liter motor. I am not sure what carb is on it. I cannot make out any numbers. My seloc book says it is a MerCarb 32 mm. Does that sound right to you? Thanks

 

[tschmidty]

Re: Mercruiser 3.0 litre problems

Yes it is most likely a mercarb, you can tell easily if it only has one idle mixture screw. There should also be a small plate attached via a screw under the flame arrestor. I wouldn't lock the choke open personally, it's there for a reason. Do you use the throttle when starting it? But yes, I would check the carb after running it to see if it is dumping fuel and flooding the engine after shutting it off.

 

[trkives]

Re: Mercruiser 3.0 litre problems

The carb does have one idle screw so that should be right. Do you happen to know the part number for the carb or the rebuild kit? I am also putting new plugs and wires on it and I would like to replace the coil as well. Do you know if the coil has an internal or external resistor? Thanks for your help.

 

[BIGALF]

Re: Mercruiser 3.0 litre problems

Check fuel first. Is there any junk in the filter screens. does is always start when cold? If so maybe you have a fuel vapor lock

 

[trkives]

Re: Mercruiser 3.0 litre problems

I drained the tank and put fresh fuel in it. It does always start when cold. Is fuel vapor lock caused by stale fuel or junk in the filter screens?

 

[ryanr623]

Re: Mercruiser 3.0 litre problems

I drained the tank and put fresh fuel in it. It does always start when cold. Is fuel vapor lock caused by stale fuel or junk in the filter screens?

Im having the exact problem. Check out my thread http://forums.iboats.com/showthread.php?t=482447

We can follow each others thread for ideas.

 

[trkives]

Re: Mercruiser 3.0 litre problems

Thanks, I read your thread. My problem does not appear to be flooding. My engine has to completely cool off to restart and when this problem occurs, I have no fuel getting to the carb. I have not had a chance to check yet, but I think I am getting vapor lock due to a weak fuel pump. I will verify this as soon as I can and let you know.

 

[BIGALF]

Re: Mercruiser 3.0 litre problems

Vapor lock is caused by the heat in the engine cover that is so hot it causes the fuel to boil in the line. That assumes that you are using regular fuel that has ethanol like most gas stations have. If your using marine fuel this should not be the problem If you temperature is hot enough in the engine cover it will cause the fuel to get to hot and cause a vapor lock. If you lift the cover before you stop and blow air in the engine well and run the engine at idle speed for about 3 to 5 minutes before you shut it off and let it sit for awhile 1 hour or more and see if it start up. If it does that might be your problem. I have been having this problem with my boat for about 2 years here in hot Florida.

 

[ryanr623]

Re: Mercruiser 3.0 litre problems

Thanks, I read your thread. My problem does not appear to be flooding. My engine has to completely cool off to restart and when this problem occurs, I have no fuel getting to the carb. I have not had a chance to check yet, but I think I am getting vapor lock due to a weak fuel pump. I will verify this as soon as I can and let you know.

Any updates? I haven't had a chance to get down to the marina yet.

After numerous forums searches I Believe that my carb is leaking into the manifold after shut down. Hence why I have to wait a couple hours or have to start at WOT to clear the fuel.

 

[Caseygolf]

Re: Mercruiser 3.0 litre problems

Do you happen to know how many hoses and plugs need to be put back in after it has been winterized? I had my boat winterized at Bass Pro and took it back for them to summerize it but they are 2 weeks out. I found three hoses and reconnected them but could not find anything else that looked like it had been taken off? Need all the help I can get thanks. I have a MerCruiser 3.0 LITRE I/O