1990 8 hp Evinrude running issues

[ShoestringMariner]

I recently picked up a clean 1990 8 HP OMC. It hadn’t been run in years so I changed the fuel lines, rebuilt the carb, changed the impeller and lower unit oil.

I ran it a fair bit this week as a kicker and it developed some running issues where sometimes it would dwindle down from 1/4 or 1/3 throttle and stall out. New poly tank and fuel line primer bulb etc. No air leaks. Vent open.

it is also very hard to start from cold. 15 + pulls with the choke on before it’ll catch. Primer bulb squeezed several times until hard. Will not fire if the choke is not fully engaged. But once running it starts 1/2 pull every time unless it runs into that running problem where it tapers off and dies. Then I have to use a choke again.

Starving for fuel?
I did not change or clean the fuel pump. I checked the fuel pump screen and it looked perfectly fine.

 

[oldboat1]

If you changed out the fuel line connector at the motor, you might go back to the old connector if you have it. And it might be worth your while to just replace the fuel pump. Try one of the cheap ones. If it solves the problem, you know it's a fuel pump issue.

 

[Vic.S]

When you experience the "running problem" try pumping the primer bulb. If that overcomes the problem then it confirms a fuel flow or pumping problem.

However that fact that you have such difficulty starting when cold suggest a carb problem. Re-clean more thoroughly and check the float and float valve including the little clip between the float arm and the needle.

But first check the compressions and report the figures
Also confirm that you can get good strong sparks from each plug lead which will juap 7/16"

Have you tried new plugs? Champion QL77JC4 or QL86C gapped at 0.030"

 

[ShoestringMariner]

If you changed out the fuel line connector at the motor, you might go back to the old connector if you have it. And it might be worth your while to just replace the fuel pump. Try one of the cheap ones. If it solves the problem, you know it's a fuel pump issue.

Thanks. I did not change the connector but I did not think to clean it if that’s even possible

 

[ShoestringMariner]

When you experience the "running problem" try pumping the primer bulb. If that overcomes the problem then it confirms a fuel flow or pumping problem.

However that fact that you have such difficulty starting when cold suggest a carb problem. Re-clean more thoroughly and check the float and float valve including the little clip between the float arm and the needle.

But first check the compressions and report the figures
Also confirm that you can get good strong sparks from each plug lead which will juap 7/16"

Have you tried new plugs? Champion QL77JC4 or QL86C gapped at 0.030"

Thanks, when it happened, the primer bulb was hard and full. It did not want to compress. I put a full carb kit into it. New float, needle, seat and clip.

Admittedly I did not check the compression because it ran great in the barrel before I went on my trip. Including idling/slow troll. (I figured low troll/idle meant compression was good or ok) but now I’m concerned. Would make sense about the hard starting.

do I need to ground out the plug wires on these to do a compression test?

Also, how do I do a 7/16” spark test.

The plugs looked new, so I only checked the gap. I’ll throw new ones in.

 

[ShoestringMariner]

When you experience the "running problem" try pumping the primer bulb. If that overcomes the problem then it confirms a fuel flow or pumping problem.

However that fact that you have such difficulty starting when cold suggest a carb problem. Re-clean more thoroughly and check the float and float valve including the little clip between the float arm and the needle.

But first check the compressions and report the figures
Also confirm that you can get good strong sparks from each plug lead which will juap 7/16"

Have you tried new plugs? Champion QL77JC4 or QL86C gapped at 0.030"

Disregard my question about 7/16" spark gap. I've found and ordered the tool. I've also read that the grounding leads are a must as I suspected all along. I'll have to find some HD alligator clips.

thanks again for your help

 

[oldboat1]

Revisiting that clip issue -- O-ring on the new one can be so tight that you may not get the clip on completely. On the other hand, an old clip/old O-ring can be too loose and give you an air leak in the system. If you get a new clip, make sure it's for an OMC motor. But my guess is a fuel pump issue. You can rebuild the little buggers, but I usually just replace them. Depending on where the auxiliary tank is located, the lift may be a little too much.

A couple of years ago, I had difficulty getting my 9.9 kicker to prime correctly -- found that leaving the fuel line connected seemed to be the solution.