Older Evinrude Engine

[Crestliner2007]

I have a tiller (pull start) 9.9 hp long shaft 2-stroke, circa 1976. Has been running well over the past 3 seasons, but this spring she's giving us problems. She's starting ok, it just that I'm only getting less than half the thrust (hp) out of her on the water. She runs fine in the barrel, but when under load, I don't get much power anymore. Had a compression test done on both cylinders yesterday and their just about the same, at 85 psi (or whatever the measurement is).

The portable tank is 3/4 full of gas put in late last fall. I use Startron additive all the time and use high test gas only, along with a 50/1 mix of 2 cycle oil. Using the same gas in my other small engines with no perceivable problems. So I'm kinda at a loss as to where to look and what kind of expense I'd be looking at! Being such an old engine, I don't want to spend a lot of bucks on her. Appreciate any feedback from you fine folks. Thanks muchly.

 

[flyingscott]

You are probably running on one cylinder. More than likely need new points and condensers do it yourself for less than $100

 

[82rude]

Also don't ignore the coils.I had the same year 15hp ,same issues ,it was the coils.Hairline fracture ,you wouldn't think that it was anything but it was the problem.Also if everthing checks out ok you could have a spun prop.You didn't exactly say but if you give it throttle is it reving up but not going anywhere or not reving up atall?

 

[jimmbo]

Spray a bit of fuel mix into the carb, you might have to remove the silencer on the carb. If it runs better, you have a fuel issue, if worse usually ignition

 

[F_R]

1974-1976 models were notorious for fouling spark plugs. Even plugs with very low time on them. Remove plugs, check for spark on both cylinders, and if you have spark, try new plugs.

 

[Crestliner2007]

Just to clarify a bit. She runs great in the tank, but when pushing the boat - under load - it just doesn't get up to where it use to be last season. Not even close it appears! Did the compression test and all is well - 85 in each cylinder. The plugs didn't "look" fouled very much. The top cylinder plug was very clean; the bottom cylinder was "wet" somewhat, not a lot. So that's pretty much where I'm at right now. Thanks for any suggestions and those offered thus far.

 

[hardwater fisherman]

While running with some insulated pliers pull off one spark plug wire at a time and see what happens. An example if you pull off the bottom one and it stays running than you know the top plug is firing. Than put back the bottom plug wire and pull off the top one and if it stalls than it is not firing on the bottom. If lack of spark I would suspect bad or dirty breaker points. If you find a no spark issue you can switch the coils and see if it follows. Also check plug wires and boots. And of course as said maybe replace the plugs.