Venture222
Recruit
- Joined
- Apr 27, 2011
- Messages
- 2
Hi guys. I've an outboard novice, and I'm hoping that someone can help me with this one...
I bought a used 1981 Evinrude 15HP outboard (pull start). When I started it the first time, it fired up after 3 or 4 pulls. I let it run for 5-10 minutes with the throttle at the START position to warm it up. It ran a little rough, but seemed to be getting better as time went by. However, when I throttled it down to let it idle, it quit like it ran out of gas. The engine started right back up with 1 or 2 pulls, but only ran for 5 seconds or so before it quit again. Almost like the fuel pump wasn't working.
So, I took apart the fuel pump and examined the pieces. Nothing clogged, ripped, or missing. I put it back together and reinstalled it.
Pulled the plugs. A little bit of gray, cloudy liquid was on the electrodes. It looked like water mixed with oil, but I figured I would try replacing the plugs. New plugs installed. Still couldn't keep the motor running.
Took off the carburetor, took it apart, and cleaned it out with Sea Foam spray. The passages and jet didn't seem blocked; the Sea Foam flowed freely through. The float bowl was starting to rust (cleaned it up with steel wool), and the float was rust-stained but still buoyant (cork type). The aluminum casting was all very clean and free of deposits or damage. I reassembled the carb with the old parts and reinstalled it. This did make a difference with the motor; I could keep it running with the throttle set at the START position, but only if I adjusted the choke in small increments whenever the motor started acting like it was going to stall out. Still couldn't run it at idle, though. Throttle her down, and she quits.
Pulled the plugs again. More milky-gray liquid on the plugs. Definitely looked like oil mixing with water. Suspecting a bad head gasket, I pulled the motor out of the tank and laid it on its back on the floor. More of that milky-gray stuff came out of the exhaust housing through that small hole on the rear of the upper part of the shaft. The puddle was probably big enough to fill the palm of my hand.
I then did a compression test to confirm the head gasket failure. 120Lbs on the top cylinder, 115Lbs (leaks down to 110 after 10 minutes) on the bottom cylinder. I then hooked up compressed air to the cylinders and got no leakage, but I didn't cycle the engine any...so I don't think I did the leak-down test properly.
I haven't done anything else yet; I have the factory service manual coming in the mail. Internet searches are getting me worried about cracked blocks and scored cylinders. I don't think this motor was very well cared for by previous owners, so who knows what the internals are looking like.
Do you guys have any ideas, based on the info here? What should I check? Is the head gasket ruled out, since the compression is good? Thanks for any help you can offer!
I bought a used 1981 Evinrude 15HP outboard (pull start). When I started it the first time, it fired up after 3 or 4 pulls. I let it run for 5-10 minutes with the throttle at the START position to warm it up. It ran a little rough, but seemed to be getting better as time went by. However, when I throttled it down to let it idle, it quit like it ran out of gas. The engine started right back up with 1 or 2 pulls, but only ran for 5 seconds or so before it quit again. Almost like the fuel pump wasn't working.
So, I took apart the fuel pump and examined the pieces. Nothing clogged, ripped, or missing. I put it back together and reinstalled it.
Pulled the plugs. A little bit of gray, cloudy liquid was on the electrodes. It looked like water mixed with oil, but I figured I would try replacing the plugs. New plugs installed. Still couldn't keep the motor running.
Took off the carburetor, took it apart, and cleaned it out with Sea Foam spray. The passages and jet didn't seem blocked; the Sea Foam flowed freely through. The float bowl was starting to rust (cleaned it up with steel wool), and the float was rust-stained but still buoyant (cork type). The aluminum casting was all very clean and free of deposits or damage. I reassembled the carb with the old parts and reinstalled it. This did make a difference with the motor; I could keep it running with the throttle set at the START position, but only if I adjusted the choke in small increments whenever the motor started acting like it was going to stall out. Still couldn't run it at idle, though. Throttle her down, and she quits.
Pulled the plugs again. More milky-gray liquid on the plugs. Definitely looked like oil mixing with water. Suspecting a bad head gasket, I pulled the motor out of the tank and laid it on its back on the floor. More of that milky-gray stuff came out of the exhaust housing through that small hole on the rear of the upper part of the shaft. The puddle was probably big enough to fill the palm of my hand.
I then did a compression test to confirm the head gasket failure. 120Lbs on the top cylinder, 115Lbs (leaks down to 110 after 10 minutes) on the bottom cylinder. I then hooked up compressed air to the cylinders and got no leakage, but I didn't cycle the engine any...so I don't think I did the leak-down test properly.
I haven't done anything else yet; I have the factory service manual coming in the mail. Internet searches are getting me worried about cracked blocks and scored cylinders. I don't think this motor was very well cared for by previous owners, so who knows what the internals are looking like.
Do you guys have any ideas, based on the info here? What should I check? Is the head gasket ruled out, since the compression is good? Thanks for any help you can offer!
