New boat owner & problems w/ 1967 Evinrude - fuel odor, arcing, sputtering

[rgnjc]

New boat owner here, and I would appreciate any help with diagnosing my motors problems. I recently purchased a 1976 seaswirl trihull with a 1967 Evinrude 33hp ski twin (Model 33752C). Being new to boating, this was a great boat to learn with. Motor looked very clean, started easily and idled great. When I picked it up I changed the spark plugs and lower unit oil (which was like sludge and super thick). The previous owner only used it a few times in the last few years, never tuned it up or did anything to it (but ran it a few weeks ago without issues).

I took it out on the lake today to see how she runs. Started great, ran great for at least 4 hours, but then I started suspecting symptoms that something wasn't right. The low rpm idle didn't sound so great anymore and it almost stalled a few times. Then when I shut the motor down there was a strong odor of gasoline. I could see gasoline around the engine and little white bubbles which would float to the surface and pop and smell strongly of gasoline. It seems to be coming from the exhaust, but I wasn't too concerned since I figured that may be normal for old motors. Later, when I headed back in, the motor lost all of its pep and power at full throttle that it had earlier and started sputtering and would only go slow. I then noticed a spark arcing on the bolt that the steering wheel cable connected to the motor. When I would wiggle the wheel left/right to make that assembly move, occasionally a spark would arc off the bolt. I loaded up my boat and went home, not sure what to think about all this. What is the best way to diagnose these problem(s)?

Picture of my motor:

 

[F_R]

The gas drainage is mostly because it was running so lousy. Every time a cylinder failed to fire, the fuel went out the exhaust instead of burning. Having said that, even when in top tune, they aren't the cleanest running motors ever invented. But should run well and be very dependable.

To get it that dependable, you have to do some tune-up and maintenance. By all means, the ignition system needs to be checked. Don't be surprised if the coils are shot, along with points & condensers which are considered normal maintenance. And the water pump impeller needs to be changed whether it needs it or not. Ignoring it only invites a cooked motor.

As for the arcing, that certainly isn't normal. Something is grounding out that shouldn't be. You are going to have to do a good checkout of the whole electrical system, boat and motor. Start with battery cables. You may need some help if you aren't very familiar with basic circuits.

 

[rgnjc]

OK Thanks! Hoping the fuel smell is a non-issue once I solve the other problem(s). I'll take a good look at the ignition system this week, and start it up at night to see if I can track down a spark arcing off anything in particular. I think my knowledge is basic enough that I should be able to figure out the electrical system, its really simple on this boat so it shouldn't be that hard to figure out.

 

[rgnjc]

Just posting a follow up to this in case somebody has a similar problem in the future. I replaced the condensers and ignition coils. They all appeared OK, and passed my test with the multimeter, although a wire or two on one of the coils appeared blackened a bit. It wasn't a lot, but I think this was the problem. I suspect the current was jumping across the burned insulation. The motor starts and runs great now. Still a bit of fuel smell but not as bad.