scottyd1977
Recruit
- Joined
- May 12, 2011
- Messages
- 4
I bought a boat around Christmas of last year with a 1984 90 horse Evinrude. It required a lot of work to the boat and to the motor to even get it ready for the water.
I have so far replaced the fuel pump, power packs, water pump, two coil packs, and rebuilt both carbs. I took the boat out the other day with 15 gallons of gas so that I could run it. This was the first run of more than 2 miles with it.
It ran great for 50 miles, but then I stopped at a sandbar on the river to let my girls swim for a bit and the motor had a bad knocking sound and lost power. We stopped and I checked the motor there for the obvious (was thinking I had a rod knocking or electrical problems.) I started the motor again to see if the knock was still there with the cover off and it was gone but the motor sounded different turning over.
To make a long story short, I got home and checked the compression on my cylinders. They check out as: 112, 108, 110, and 8. Obviously the cylinder with 8 psi of compression is the problem. I have not torn into the engine yet to start repairing but am wondering, if a piston ring was burnt/broken wouldn't it have more compression? Could I have blown a hole in the piston? Could it have slung a rod without actually throwing the rod out of the crankcase? Is this motor worth the work to fix it?
Thanks for the advice!
I have so far replaced the fuel pump, power packs, water pump, two coil packs, and rebuilt both carbs. I took the boat out the other day with 15 gallons of gas so that I could run it. This was the first run of more than 2 miles with it.
It ran great for 50 miles, but then I stopped at a sandbar on the river to let my girls swim for a bit and the motor had a bad knocking sound and lost power. We stopped and I checked the motor there for the obvious (was thinking I had a rod knocking or electrical problems.) I started the motor again to see if the knock was still there with the cover off and it was gone but the motor sounded different turning over.
To make a long story short, I got home and checked the compression on my cylinders. They check out as: 112, 108, 110, and 8. Obviously the cylinder with 8 psi of compression is the problem. I have not torn into the engine yet to start repairing but am wondering, if a piston ring was burnt/broken wouldn't it have more compression? Could I have blown a hole in the piston? Could it have slung a rod without actually throwing the rod out of the crankcase? Is this motor worth the work to fix it?
Thanks for the advice!
