1990 evinrude 20 h.p.

Joined
Sep 21, 2010
Messages
13
The last two times out on the water i have had this problem. When at full throtle for about 8 min my engine cuts down to almost idle then surges to about half then drops back down to idle. This happens at a rate every second or so and doesn't stop. I have to throtle back to an idle and it will run ok at idle but if i try to go full speed it does it again. After i idle for a time like 5 min. i can go full throtle for awhile again untill it starts pulsating again. Please help me ... Thanks..
 

jbjennings

Captain
Joined
Jul 18, 2007
Messages
3,903
Re: 1990 evinrude 20 h.p.

First, make absolutely sure your motor is not overheating. It should be running at very close to 140 degrees.
Second, make sure the vent is open on your fuel tank and pump the primer bulb by hand while your motor is running and see if that changes the problem. If so, it could be your fuel pump.
Good luck,
JBJ
 
Joined
Sep 21, 2010
Messages
13
Re: 1990 evinrude 20 h.p.

First, make absolutely sure your motor is not overheating. It should be running at very close to 140 degrees.
Second, make sure the vent is open on your fuel tank and pump the primer bulb by hand while your motor is running and see if that changes the problem. If so, it could be your fuel pump.
Good luck,
JBJ

I am not sure how to read the temp, but when this was happening on the water i checked the vent on the fuel tank and sqezzed the primer bulb and it did not change the problem. Thank you for the info and if you have a way to check the temp let me know...
 

Cofe

Lieutenant Commander
Joined
Apr 23, 2009
Messages
1,883
Re: 1990 evinrude 20 h.p.

You should be able to place your hand on the head by the spark plugs after the motor is warmed up. 140 degrees will feel hot but won't burn you. You can also get a thermal temperature gun at a auto parts store or harbor freight.
 
Joined
Sep 21, 2010
Messages
13
Re: 1990 evinrude 20 h.p.

You should be able to place your hand on the head by the spark plugs after the motor is warmed up. 140 degrees will feel hot but won't burn you. You can also get a thermal temperature gun at a auto parts store or harbor freight.

Thank you for the info... It is appreciated....
 
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