1989 Evinrude 120 bogs while planning.

[biglurr54]

I have a 1989 120 Evinrude the has not been running well this season. Yesterday it was running rough while idling around the lake. While idling it would miss fire and skip a lot. Today I went out and got new plugs knowing they are a problem area. Put new plugs in and all the old plugs were black and very wet. Motor started right up and same issue. When we tried pulling a skier it would not run smooth. It wouldn't pop the skier up like it used too. Once the skier let go the boat would hop up on plan then it would clear out and start screaming down the lake normally. I didn't replace my water fuel separator this year but it only has about 20 gallons through it so far so I figured it was ok. Any ideas what could be wrong?

 

[Daviet]

Re: 1989 Evinrude 120 bogs while planning.

I would start with a couple of tests, compression and spark, to make sure that your engine is running on all cylinders.

 

[biglurr54]

Re: 1989 Evinrude 120 bogs while planning.

Compression was 130 on all 4 cylinders. I put a new water fuel separator on. I cleaned re-gapped and all the plugs. (one set brand new, other set has 10 hours on them) I than ran the boat a while. Same issues, missing at idle speeds and bogging down when trying to plane out. Once up and planning it will clear out and sound smoother but not turning the RPM's I need. I took all the plugs back out and found the cylinder that had the oily plug and put a new plug in and a new wire. Same issue of skipping at idle. I don't have a spark tester but if they don't cost much I may pick one up today. Any other ideas on what to check? Does it sounds like a power pack on that cylinder?

 

[biglurr54]

Re: 1989 Evinrude 120 bogs while planning.

How can I test if its a powerpack or just a coil?