runs fine cold, floods when hot merc 140 volvo

y2kdon

Recruit
Joined
May 11, 2003
Messages
2
Having a problem with a 1985 mercruiser 140HP with volvo 4 cylinder engine and 2 barrel carb. Carb has a tag with the numbers:1389-8490. It runs great for the first 30 minutes or so. After that it idles rough. If you shut it off, it floods when you try to restart. Once you get it started, it often dies when put in gear. After you get it in gear and moving, it runs fine at all speeds above idle.<br /><br />Automatic choke appears to be working fine meaning it opens up after engine has run for a few minutes. I thought the float may have had a hole in it but checked and it is OK. Idle speed appears about right. My experience with carbs is minimal. I'm at a loss. Any help appreciated.
 

Gene70

Petty Officer 3rd Class
Joined
Apr 18, 2002
Messages
95
Re: runs fine cold, floods when hot merc 140 volvo

I doubt you have a mercruiser with Volvo engine. A Mercruiser does not have a Volvo outdrive. Mercruisers and Volvo both use the 140 Chevy base engine. There are a lot of differences between the two. Your problem with running is carburetor. Maybe you have water in the system. See if you have a fuel water separator on the engine. If you don't then you need to put one on it. Kit the carburetor. This should take care of your problems.
 

Patrick123

Cadet
Joined
May 11, 2003
Messages
27
Re: runs fine cold, floods when hot merc 140 volvo

I don't know if this applies to boats or not but I had a the exact same problem on a pickup. It stumped me forever but my friend spotted it right away. It was the fuel line was too close to the exhaust manifold. The fuel must have boiled in the line or something and forced it past the needle valve after the engine warmed up, even with the engine off but still warm it would be flooded like crazy when you tried to restart. Re bent the fuel line and added a zip tie and problem solved. Good luck.
 

y2kdon

Recruit
Joined
May 11, 2003
Messages
2
Re: runs fine cold, floods when hot merc 140 volvo

I considered the vapor lock problem. The fuel pump is on one side of the engine and the carb on the other. The metal fuel line runs up and over the top of the valve cover with a metal clamp to the valve cover. Will try to insulate the fuel line and see if that helps.<br /><br />I also found a Mercury service bulletin that seems to describe my problem. Ordered the needle and seat assembly for the carburetor it recommended and will try that.<br /><br />I was told by the previous owner that the engine was made by Volvo. Cant find it documented anywhere. The owners manual says it is a 181 cubic inch/2.97 Liter. The outdrive is definitely Mercruiser.<br /><br />Where can I find info on fuel/water separator?
 
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