Salty Ducks
Recruit
- Joined
- Oct 2, 2006
- Messages
- 5
I'm having a problem with my 1990 Evinrude 70hp losing power while on plane. The problem has been intermittant and it doesn't show the same exact symptoms every time out. I have a really good mechanic who does my work for me, but when the problem first surfaced I immediately checked all the obvious stuff related to gas. New, gas, new tank, new hoses, etc. Same problem, runs good at idle AT FIRST then put it up on plane, run for a bit then it looses power and sometimes cuts off, but most of the time just bogs down until I am at 3/4 throttle and barely making way.
So after checking the gas I took it to my mechanic who suggested an ignition problem. First they checked compression which was on the money between all 3 cylinders....and had good spark on all 3 cylinders. They put it in the test tank and couldn't get it to fail. Being an intermittant problem my mechanic suggested that it could be the power pack. I agreed and got it replaced. They tested it again after replacing the pak - all looked good. I took the motor out.....same problem reared it's ugly head. Took it back, ran it in the test tank and I was there. It ran like a scolded dog for 20 minutes - no problem. Well, he said he would still dig deeper...took the flywheel off and the stator showed signs of melting. Went ahead and replaced that...while he was in he also replaced the recitifier. Felt certain this had to be the problem and that the motor was failing after heating up. Tested the boat in the tank after replacing the stator and all was good. I get the boat and take it out.....same old problem. At first it seemed like it might do OK.....ran OK at idle speed and too off like a shot from a gun when putting up on plane - for a second I thought all was good....then it bogged down again....AHHHH!!!
Going back to the basics I got a spare gas tank that my buddy had been running on his Evinrude all week and tried that just to rule out gas again. Same old problem........sounds like it's running on 2 cylinders or not getting gas. No problem starting and it normally runs at idle speed well and just gets worse when runnning it hard.
My mechanic says they could trouble shoot it fairly easily if they could just get it to fail in the tank. Frustrating that it runs fine in the tank, but awful when out on the water.
Hopefully he ran it in the tank again this evening and got it to fail. If not I suggested going ahead and replacing the 3 coils. He also said he was going to pull the carbs and take a look for any varnish, etc.
So does anybody have any bright ideas. This is the most frustrating thing I have gone through with an outboard and I have had a bunch. Maybe a reed valve?? I don't think that would be intermittant though.
Any thoughts or help would be appreciated!
So after checking the gas I took it to my mechanic who suggested an ignition problem. First they checked compression which was on the money between all 3 cylinders....and had good spark on all 3 cylinders. They put it in the test tank and couldn't get it to fail. Being an intermittant problem my mechanic suggested that it could be the power pack. I agreed and got it replaced. They tested it again after replacing the pak - all looked good. I took the motor out.....same problem reared it's ugly head. Took it back, ran it in the test tank and I was there. It ran like a scolded dog for 20 minutes - no problem. Well, he said he would still dig deeper...took the flywheel off and the stator showed signs of melting. Went ahead and replaced that...while he was in he also replaced the recitifier. Felt certain this had to be the problem and that the motor was failing after heating up. Tested the boat in the tank after replacing the stator and all was good. I get the boat and take it out.....same old problem. At first it seemed like it might do OK.....ran OK at idle speed and too off like a shot from a gun when putting up on plane - for a second I thought all was good....then it bogged down again....AHHHH!!!
Going back to the basics I got a spare gas tank that my buddy had been running on his Evinrude all week and tried that just to rule out gas again. Same old problem........sounds like it's running on 2 cylinders or not getting gas. No problem starting and it normally runs at idle speed well and just gets worse when runnning it hard.
My mechanic says they could trouble shoot it fairly easily if they could just get it to fail in the tank. Frustrating that it runs fine in the tank, but awful when out on the water.
Hopefully he ran it in the tank again this evening and got it to fail. If not I suggested going ahead and replacing the 3 coils. He also said he was going to pull the carbs and take a look for any varnish, etc.
So does anybody have any bright ideas. This is the most frustrating thing I have gone through with an outboard and I have had a bunch. Maybe a reed valve?? I don't think that would be intermittant though.
Any thoughts or help would be appreciated!