mercruiser 140 surging when warmed up

[Robscobia]

I have a mercruiser 140. I just gave it a complete tune-up. Plugs, wires points, condenser, roter button, fuel filter and replaced the water pump in the foot. All gaps are set per engine specs. I took the boat out for a test run. It ran great for about 30 min. then started surging. Does any one have any ideas?<br />Also when I shut the boat off to check the point gap. I told my friend to hit the ignition and the starter stuck in the on position and kept turning over and over until the battery ran dead. I assume its a bad solenoid. Any other Ideas?<br /><br /> thanks<br /> Robert

 

[horndog]

Re: mercruiser 140 surging when warmed up

sounds like a heat issue. Did you observe the water temp when it started to surge? Did the exhaust elbow feel hot(not able to hold your hand to it, should feel "warm")<br /><br />Your coil maybe gone ape-chit, you need to give more info. Go take your boat out and check those items again or run it on the hose and see if thats the issue.

 

[Robscobia]

Re: mercruiser 140 surging when warmed up

Thanks for the info!

 

[record hunter]

Re: mercruiser 140 surging when warmed up

usually a motor surges because it has a vaccum leak. By some carb cleaner and spray it around the throttle linkage and the carb base. If you do not hear the rpm go up its ok proceed to spray around intake manifold if there is a leak the rpm will go up. Dont be confused thoughto be careful not to spray into the carb its easy to do and you could think its a vacuum leak when its not .As far as the starter its soinds like you might have a bad ignition key maybe some water got in .That happen to me and my problem was I had alittler salt watter in the key. Good luck

 

[horndog]

Re: mercruiser 140 surging when warmed up

if it runs fine then goes haywire then the vacuum leak isn't a problem since it would be noticable from the time he fires it up, wouldn't you think?

 

[akriverrat]

Re: mercruiser 140 surging when warmed up

unless heat opens up a seam somewhere.