Late 80's 8hp Evinrude Problems

Idles great, revs great in neutral, but boggs down under load. Doesn't die but I can only do 4 - 5 mph. Primer bulb stays firm. This model doesn't have a choke. It has a primer pump that you pull out a few times before cold start. If I pump if fast enough, I can get up on a plain and it runs wide open. Well almost. I'm not that fast and it's hard to do.

So after searching around on this site and a bunch of google searches, I am thinking the high speed jet is clogged and I need a good cleaning and carb kit. But I have noticed a couple other things going on and want to know if they could be causing the problem.

1. When pulling the knob on the primer pump, it leaks a small amount of fuel around the shaft. Could this be causing air to suck in instead of fuel when trying to run WOT?

2. Also, a decent about of fuel leaks out from the carb gasket where it mounts on the motor when pulling on the primer knob. Again wondering if this is allowing air in instead of fuel?

It did sit for a while and I wasn't always able to use ethanol free gass. I took a different tank and put 2 gal of ethanol free and a good bit of sea foam in it and have ran about a gallon of it.

Squeezing the fuel bulb didn't help so pretty sure fuel supply isn't the problem...assuming the hose isn't connected backwards. Sounds like the fuel is not being pulled through the main circuit in the carburetor.

You said your engine is in the 80s and that it has a primer. That means your engine is 1986 or newer. You have the carb with a nozzle-well(plastic jet holder) and a flex tube(small rubber hose) inside the carb. The hose runs from the nozzle-well up to the carb body. Two main causes that I have found are the clogged main jet(like you said) or that rubber hose crumbled and fell off. Check the gaskets above and below the nozzle-well too. If you don't see the hose look for pieces in the bowl. The carb kit sold by Evinrude has all the gaskets and the hose. You need to work carefully the hose needs to be treated gently.

Take your fuel system apart slowly and make note of anything that doesn't look right. There can be more than one problem...but the little hose probably crumbled from the ethanol fuel.

Float level is important on all OMC carbs. If you don't have the factory gauge you can get reasonably close by 'eyeball'. With the carb body inverted the float should be just about parallel to the gasket surface.

To get a better idea of exactly what to look for, go to Evinrude.com. Click on parts, find your year, model, and select carburetor. Enlarge and study the diagram to see what yours is supposed to look like.

A clean carb with all the parts in their respective position, all good gaskets, and all fasteners tightened properly will work right. All linkage adjustments have to be by-the-book. Buy or borrow the factory book. Do what it says in ABC order. Those 6, 7.5, and 8hp(1980 and up)are picky about that.


Here's a video of a 1987 Johnson 8hp on a 12ft 1967 Mirrocraft rowboat:
https://www.dropshots.com/boat2fast#date/2012-05-29/15:12:22

Here's a video of a(different?)1987 Johnson 8hp on a 12ft 1984 BlueFin rowboat(you can hear the engine hitting the rev limiter:
https://www.dropshots.com/boat2fast#date/2012-10-07/13:34:56

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Boat2fast - Perfect explanation and solution for his problem! Way to go.
I took the liberty of looking through a couple of your videos....hope you don't mind.
That '55 Johnson 10hp is gorgeous! 21mph with two onboard as well...that's great!

Hey Pappy, thanks for the kind words.

No I don't mind, look all you want.

Most of us who use this site share common interests. Makes it fun.

Thanks for taking the time and explaining this. Pretty sure it's a 1988 model. It has been a great little motor. Really surpirsing how strong it is and for a while I was wondering if was a 9.9 with 8 stickers. Then I found out about the serial number. It pushes my 1436 pretty fast by myself and no gear. Have hit 23 but usually runs 21 and 16 with two people and gear.

I went to a shop yesterday afternoon and they didn't have the kit in stock but had some gaskets and gave one to me free of charge. Told me to go ahead and change it out and order the kit if nothing changes. From what you say about the hose in there, sounds like I sould go ahead and rebuit the carb anyway and I reckon I should go ahead and replace all the hoses going to the carb also. I will print the diagram and probably take some pics to help remember how to put it back together.