Aquatical
Cadet
- Joined
- Sep 12, 2010
- Messages
- 8
I bought a 1988 small 2.5 HP Johnson for use with my canoe a few weeks ago, it looked to be in great condition, started up good, and good compression in both cylinders (around 80 psi)- ran it the first time for around 20 mins on the lake, gas/oil at 50:1, sounded great, then started to sputter and die, would not restart right away but did eventually back at the dock. I took out the spark plugs, they were the ORIGINALS and in bad shape and replaced them. Took it out a second time, ran great for 40 mins, then I idled for a bit and then sounded rough and funny for a few seconds, clanged dead, and the flywheel seized- yikes.
At home, I was able to unfreeze it while attempting to take off the flywheel nut. I sought advice on this forum as to what the issue was, and folks pointed to overheating, which sounded good, as I was sure the impeller was the original too, and maybe unable to cool the engine at idle. So I took off the lower unit and replaced the impeller, gear oil, and new seals. Also took off the carb and rebuilt it. Felt great about things.
Yesterday, I got her running at home in a test bucket for 10 mins, sounded great and set the low speed idle, idled well, with no evidence of overheating (the head felt warm and could be touched).
Took it out on the lake, ran it WOT for 10 mins, then suddenly began to sound rough, like it was dying. Shut it off and tried to restart it over and over to no avail- (either no fuel or spark kinda of nothing).
An hour or so later at home, put it on the stand, and after a few tries, got it to restart, but it sounded terrible from the get go, then died with a clank- it had seized up again.
I took out the plugs (see picture) and noted a huge difference- the upper cylinder plug to the left was nice and brown, the lower one to the right is really oily. Could it be that my problem all along- a sudden lack of spark to JUST ONE PLUG? And could that explain the sudden roughess because the engine was running on one cylinder? And maybe could that explain why it happens after 10-20 mins- kinda sounds electrical.
Now my problem is the seized powerhead. Can't move the flywheel more than one-half revolution, the upper piston moves up and down but the lower piston is stuck. If one piston is stuck, does that mean I am screwed? I can't invest any more in trying to fix the powerhead AND fix an electrical problem. Any advice is much appreciated.
At home, I was able to unfreeze it while attempting to take off the flywheel nut. I sought advice on this forum as to what the issue was, and folks pointed to overheating, which sounded good, as I was sure the impeller was the original too, and maybe unable to cool the engine at idle. So I took off the lower unit and replaced the impeller, gear oil, and new seals. Also took off the carb and rebuilt it. Felt great about things.
Yesterday, I got her running at home in a test bucket for 10 mins, sounded great and set the low speed idle, idled well, with no evidence of overheating (the head felt warm and could be touched).
Took it out on the lake, ran it WOT for 10 mins, then suddenly began to sound rough, like it was dying. Shut it off and tried to restart it over and over to no avail- (either no fuel or spark kinda of nothing).
An hour or so later at home, put it on the stand, and after a few tries, got it to restart, but it sounded terrible from the get go, then died with a clank- it had seized up again.
I took out the plugs (see picture) and noted a huge difference- the upper cylinder plug to the left was nice and brown, the lower one to the right is really oily. Could it be that my problem all along- a sudden lack of spark to JUST ONE PLUG? And could that explain the sudden roughess because the engine was running on one cylinder? And maybe could that explain why it happens after 10-20 mins- kinda sounds electrical.
Now my problem is the seized powerhead. Can't move the flywheel more than one-half revolution, the upper piston moves up and down but the lower piston is stuck. If one piston is stuck, does that mean I am screwed? I can't invest any more in trying to fix the powerhead AND fix an electrical problem. Any advice is much appreciated.
