1984 5.7L GM OMC Stringer Carb Problems

[budlo89]

Just bought this 1984 Kayot Deckboat with a GM 5.7L and Rochester four barrel. Took it to the river for the first time cranked after a few tries. Rode around at idle and higher RPM for about three hours then when going back to idle or neutral it would not stay cranked. I had to pump the throttle several times and then it would die each time I put it back in gear. After fighting with it for a while I was finally able to get it in gear and go. I then found that I had to move the throttle back and forth slightly to get it in higher RPMs once ther it ran fine. <br /><br />My neutral RPM is around 600-700. My RPMs don't seem to be fluctuating. Temp. runs below 160. Oil pressure between 20 and 40 PSI.<br /><br />I'm not sure if I'm running to lean or to rich.

 

[Laddies]

Re: 1984 5.7L GM OMC Stringer Carb Problems

Sounds like varnish came loose in the carb and it needs to be cleaned

 

[rbezdon]

Re: 1984 5.7L GM OMC Stringer Carb Problems

I dont know if you have one, but I get the same symptoms when my ESA is not adjusted properly.

 

[budlo89]

Re: 1984 5.7L GM OMC Stringer Carb Problems

I do have an ESA. I'll check out the adjustment tommorow. Not sure how that may effect me only when it has been running a while.

 

[fisherman73]

Re: 1984 5.7L GM OMC Stringer Carb Problems

I would consider a possible vapor lock condition. After you have run for awhile your engine compartment builds up enough heat. Maybe you are spitting some liquid and some vapor into your carb. Possibly pumping the thottle will get enough fuel into the motor to make it run

 

[rbezdon]

Re: 1984 5.7L GM OMC Stringer Carb Problems

Mine was not so much just hot but more random. I found the Cherry Switched were sticking some times, it just depended on the time. I found that loosening the screws that mount the body of the switch to the shift bracket helped. Eventually I replaced the switches. I just put a post on another thread to get the switched. They were like $50 each from the dealer but only around $15 from this link. Check the one called "where can I find an ESA for my OMC". There is also an excellent site from a guy nemed stuart on adjusting the shift system. I posted this link as well as seveal of other guys have too on other threads. Search on "stuart".

 

[budlo89]

Re: 1984 5.7L GM OMC Stringer Carb Problems

Thanks fisherman73. <br />If it is a vapor lock situation, what can I do about it?

 

[budlo89]

Re: 1984 5.7L GM OMC Stringer Carb Problems

I checked my ESA and the overstroke switch was not engaging. The interupter switch would engage sometimes and sometimes not. I found the spring controlling the switch was so strong it would move the shift cable before it would engage the switch. need to try it running now.

 

[budlo89]

Re: 1984 5.7L GM OMC Stringer Carb Problems

Ran with the Muffs and it dropped to around 400 RPM from 700 while engaging gear and then went back to 700 before throttle kicked in. Can't wait to try it on the water!