My last trip with the boat had some issues. Let’s try to diagnose it, shall we?
As I mentioned in my previous post, the motor wouldn’t idle at the end of the day. With a little creative use of the trolling motor, I was able to get the boat on the trailer, but it was a big hassle. This is not how I want to finish a day of boating and fishing.
There are several issues that can cause an engine not to idle properly. The easiest to fix is to replace the spark plugs, as fouled plugs don’t spark as well. It could also be something with the carburetors or with timing.
I pulled out the cylinder number 1 spark plug.
It is a little bit worn and is covered in oil. The oil could either be due to the fogging that was done during winterizing, or is the two-cycle oil from the day’s run. Also notice these are surface discharge plugs. There is no little electrode sticking out.
Plugs run between $2 and $7 each depending on where you go. Amazon had them for $4 each, but Advance Automotive had them for $3 and I had a 20% off coupon code if I ordered them online and picked up from the store. The cheapest was with Summit Racing for $2, but there was $10 shipping. Guess what I got them from.
It took about an hour to pull the six plugs and run a compression test on the cylinders since I was curious how they were doing.
When you compression test, the pressure should be at about 110 – 130 PSI, with no more than 10 PSI difference between them. If you are curious, go to YouTube and lookup how to do a compression test.
The boat came back with: 72 82 79 75 80 73 for cylinders 1 – 6. They are within 10 PSI of each other, but I’m going to say the motor has low overall compression. It is a 30 year old engine, with who knows how many hours on it. Plus, who knows how it was cared for. Did it ever starve for oil?
After the compression test, I put in the new spark plugs and started it up.
It now starts and idles; a major improvement. I’m guessing it needs to have the carburetors adjusted or rebuilt. It will require additional testing on the water to see. But good news is that it runs again.
I added some SeaFoam to the tank and an enzyme based fuel conditioner. I’m hoping the next time I take it out will clean out any carbon in the motor and maybe free up the rings a bit. With luck, I’ll get some better compression out of it.