Logo
FULL SITE MENU

Troubleshooting - 91 Evinrude 40hp

F

fat.tires

New member
Hi All - New to the forum and looking for some troubleshooting advice on a 91 Evinrude 40hp

Motor has good compression, been running fine no issues for the past 8 years I have owned it.
Fairly regular use on a 15' Klamath aluminum, side consol setup

I had not used the boat for about a month, and went out last weekend. After warming it up and idling along for 10 minutes, I was running on plane at about 3/4 throttle for a couple minutes when the motor RPM began to slow down, as if it was not getting enough fuel. After throttling back, it won't get on a plane. In water - it idles fine, but won't get going much above idle RPM. Out of water (with clam shell on) - it revs high in neutral or in gear.

Fuel line and components are good, new ball, new connector to the motor. Ball is firm. Fuel filter screen is clean. No obvious air or fuel leaks.

Any advice on what to check into?

Thanks -
FT
 
It will rev on a hose as there is no work to do and that is not a good test!------Does spark jump a gap of 7/16" on both leads ?-----Has waterpump been checked / serviced ?--And of course what are the compression numbers?-Does timer base rotate when throttle is advanced ?
 
Gotcha, figured that may be the case. Compression was 123/125 a couple months back, I'll re-check compression. Get new plugs, check spark. Waterpump is new, so is lower end gear oil. I'll check the timer base rotation at the same time.

Is there a way to troubleshoot the fuel pump?

Right now I am guessing it's a clogged jet, so i'll be going through that process at some point as well.

Thanks for the suggestions -
FT
 
If motor operation changes when the manual pump is operated then there may be a problem with the motor fuel pump.-----If you are running with a VRO pump or a simple pump on the side of #1 cylinder it is worthwhile to take the pump apart for inspection.---Not hard to do.
 
Back
Top