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evinrude 20 hp cough

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Mhill

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Hi all new to this forum I have a 84 Evinrude 20 hp picked it up a few weeks ago for 300 bucks. I had to put a rewind rope on it gave it some new gear oil and a fresh set of plugs threw it in the test tank and to my surprise it started !!!!! The motor ran ok but not great and seems to have a lean cough ?? when you give it a little bit of choke it smooths out and runs ok....... With out the choke out a bit cough, choke, sputters and when it coughs hard enough it will quit so rebuilt the carb drilled out the welch plugs, disassembled the rest and submerged it in carb cleaner re assembled after a couple days soak and still same problem!! I have adjusted the jet in and out till I found the sweet spot but still not much improvement on the low rpm idling and from just off idea rpm to wot is all good revs out nice and sounds pretty good.

Im stuck thinking its electrical possibly but also believing it not electrical because of the fact that the choke helps smooth it out.

throw me some ideas tell me what you think
thanks for any of your help
 
Mhill said:
Hi all new to this forum I have a 84 Evinrude 20 hp picked it up a few weeks ago for 300 bucks. I had to put a rewind rope on it gave it some new gear oil and a fresh set of plugs threw it in the test tank and to my surprise it started !!!!! The motor ran ok but not great and seems to have a lean cough ?? when you give it a little bit of choke it smooths out and runs ok....... With out the choke out a bit cough, choke, sputters and when it coughs hard enough it will quit so rebuilt the carb drilled out the welch plugs, disassembled the rest and submerged it in carb cleaner re assembled after a couple days soak and still same problem!! I have adjusted the jet in and out till I found the sweet spot but still not much improvement on the low rpm idling and from just off idea rpm to wot is all good revs out nice and sounds pretty good.

Im stuck thinking its electrical possibly but also believing it not electrical because of the fact that the choke helps smooth it out.

throw me some ideas tell me what you think
thanks for any of your help
Click to expand...
Does the 84’ have a true choke or the Primer?I have a 1985 With a primer and had some similar issues..and did the carb also which helped.Pulling out primer fed more gas and made it run better and that led me to the idle circuit which had a partial clog.I also found air leaks.one was the fuel pump gasket screws needed tightened even though they were pretty tight a slight turn sealed the gasket off to the block.This alone was making it run lean.Check all hose connections.
 
Ok very good thanks I’ll do some looking around maybe tomorrow and I’m going to say it a choke the plastic handle only moves a butterfly on the carb
 
Mhill said:
Ok very good thanks I’ll do some looking around maybe tomorrow and I’m going to say it a choke the plastic handle only moves a butterfly on the carb
Click to expand...
I failed to mention if the spark was tested for a 7/16 air gap and compression test was done which is what is usually recommend on this site by the gurus.After the basics maybe a link and sync check is in order.?
 
Ok sorry for the delay life is busy at the moment so here is a quick update compression is 125 top 120 bottom, spark is blue/purple at 7/16 gap, fuel pump gasket was ok wouldn’t say great but probably still sealing. Top spark plug was a good burn color bottom plug was black/ oily!! Hoping to check more hoses and what not next time I get a chance
 
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