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OMC V4 140 Hard start and idling problems

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Mickey44

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I have just recently aquired

I have just recently aquired a 1987 OMC V4. The eng. is difficult to get started and keep running at low speeds. I have found that I must pump the bulb to get the eng restarted if I shut the eng down for 30 min or more. The eng will sometimes quit while running if I run continously for about thirty min. then I must pump the bulb up again to get started. Eng. will stall whenever operating at low speeds like when docking or driving onto trailer. Help?
 
What does a compression test

What does a compression test show?? Does each sparkplug wire show a spark that will jump a gap of 7/16".Those engines had some problems with the crankshaft seal ring and that is not an easy thing to check out.
 
" I no expert, ..... but have

" I no expert, ..... but have tinkered a bit.

If pumping the bulb helps to get you started, and at low speeds maybe die out .... then I would begin to wonder if you are perhaps looking at a fuel pump that is weak.

Seems to me that a weak pump at low rpm's would tend to give weak delivery at low rpm's but at higher rpm's, if its just a bit weak, it may deliver enough to keep you going.

Just my 2 cents worth .... and you may not be able to sell it for a penny ... but I would first check the fuel delivery before going any further.

You already seem to have it at least associated with fuel ..... go from there. "
 
Just one more thought. As you

Just one more thought. As you draw fuel from the tank it will form a vacume unless the tank can "breath" so to speak. There should be a valve of sorts there that will let air in as needed but prevent fuel from spilling out. Should that peice be clogged the effect would be that the longer the engine runs the more vacume you will form in the tank eventually overcoming your fuel pumps ability to draw in fuel to be pushed to the carb.
 
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