4hp evinrude start and run problem

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Doug Ahrenholz

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Aug 27, 2004
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2
I have a 1977 4hp that requires a lot chocking and pulling to get started. once it starts it idles great but the wot rpms vary up and down, and after shutting down for a few minutes it has to be chocked to start again. I have put in a carb kit and replaced the fuel pump but it didn't help.I checked the compression which was 70psi on one cyl and 75 on the other. anyone have any ideas? I don't have a clue. Doug
 
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Paul Moir

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Nov 5, 2002
Messages
6,847
Re: 4hp evinrude start and run problem

Hmmm - that's a tough one.<br />When the WOT rpms vary - is it a sudden change?<br />What do the spark plugs look like?<br />When you rebuilt the carb, did you set the float even with the casting rim when the carb was turned upside down?
 
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cobra 3.0

Lieutenant Commander
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Jul 31, 2003
Messages
1,797
Re: 4hp evinrude start and run problem

When you did your carb, did you change the float? If you can press your nail into the float and see wetness coming through, the float needs to be replaced.
 
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Doug Ahrenholz

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Joined
Aug 27, 2004
Messages
2
Re: 4hp evinrude start and run problem

the rpms drop suddenly and the engine seems labored, also if I take the top cover off the rpms come back up. I did change the float and checked that it was level with the bowl. spark plugs are new.I read somewhere the spark is suppose to jump a 1/2" gap is that correct?
 
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Paul Moir

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Nov 5, 2002
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6,847
Re: 4hp evinrude start and run problem

More like 3/8 - 7/16. What sized gap is it capable of jumping?
 
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