Brief recap, bought a boat a few months back as a newbie boat guy...great deal...yeah. Early 80's 140hp head plopped on an 82 90hp rebuilt leg. Ran fine for a day then blew the rings out of a cylinder. Bought an 81 90hp Johnson parts motor with 120 compression on all 4 cylinders that runs. Took that power head and put it on rebuilt leg. All good so far. Good spark, rebuilt carbs, redid head gaskets after replacing water diverters and cleaning cooling passages, did a thermostat kit and new impeller/housing kit for leg as well. Idles fine in driveway on muffs.
So...first time out yesterday and couldn't get over 1200-1500 rpm and motor would die. I noticed at last outing it seemed to run worse on one tank than the other, but I thought it may have been older gas. This time I have new gas with startron additive in both tanks and also Seafoam in 1 tank and fresh gas. Also running about 45-47:1 mixture, little richer to be safe after recondition. Anyways, I switch tanks and suddenly it chokes to life and I have a great couple of runs, starting out slow then up to full speed/power. Great. Then it starts choking a bit again and dies on going into gear. At this point I'm fairly close the marina. Dies again so when I go to restart...nothing. Starter doesn't turn or anything. Fire up the kicker and back to dock. Pull the cover and the starter's stuck in the flywheel. Pry it loose and fire it up again. This time I notice the fuel line is kinked. Same fuel line boat came with, as are the tanks. Up to the marina shop to get new fuel line and bulb and connector. They had no tanks in. Starts up fine and out I go again.
This time it still seemed a little starved so I gave it a couple of shots from the key choke and it jumped to life. Hmmmm... Anyways, after this I had a great half dozen runs back and forth out in the bay. Feeling pretty good until I ran out of gas in the "good" tank. Switched over to the "bad" tank and there's definitely something up with that tank. It ran but just didn't have the "life" the other tank did. Ok fine, can deal with that. Had it at idle for a minute to tidy up a couple things before I came back in and it died. Went to restart and starter spins but won't engage flywheel. Great. Fire up the kicker and back to dock.
So that was my day. Got home, replaced starter with one from 140 and flushed the kicker and 90 (bay is saltwater). All good. Decided to pull the plugs and test compression. 116-120-118-120 1,2,3,4 respectively. Ok good. Plug one had light tan crusty dry deposits on it though. 2,3,4 plugs all a little black and oily, but identical in appearance. Manual says that it is ash deposits...light brown or white and result from using fuel or oil additives.
Now some questions:
Ok, I had additives in both tanks but why the deposits on cylinder 1 and not the others? Or is this a fuel issue?
I also noticed at idle now there's an occaisional miss. I didn't notice it a various rpm's while running but at idle it's there. I did a link 'n sync but I'm not an expert so maybe I should revisit that. I haven't had a chance to do a WOT timing yet, but that shouldn't affect it idling should it?
While I was on the water at WOT, I couldn't get over 4000rpm. Manual says this motor should be 4500-5500 WOT. I noticed there's a 1/4 inch line from the fuel pump to where the inline gas filter used to be (I took it off and tossed it when I put on the new fuel line but got a male-male hose adapter). In hindsight I should have just run 3/8 straight to the fuel pump. Could this restriction have caused my rpm limit. Or reeds? I'm also going to get 2 new tanks/fittings because even the "good" fuel tank I think leaks air into the line.
I noticed when I put the new line/bulb on, I couldn't fully pump the ball to firm on one and only "almost" firm on the other so I suspect both tanks are faulty.
Oh one more thing. I took the air silencer cover off at home and noticed the inside cover had a coating of oil on it. I'm not sure if this is from bad reeds or just the fact I'm running a bit rich. Also the hose that connects to the lower rear of the housing isn't tight. Very loose so I may tie-wrap it tight later today. Could reeds cause the type of fouling on plug #1 as described above? I could pull the intake off the 140 and see if the reeds are good and will fit the 90 or just get new ones I guess. I haven't had the intake off the 90 to visually see if they're good or not. I had previously assumed the were ok because it runs pretty good when I can keep fuel to it.
Anyways, sorry for the long post but I want to thank in advance everyone on this Johnson forum and Iboats in general. Your advice and knowledge has saved me thousands, literally. I hope I can learn enough to return the favor here...
Cheers.
So...first time out yesterday and couldn't get over 1200-1500 rpm and motor would die. I noticed at last outing it seemed to run worse on one tank than the other, but I thought it may have been older gas. This time I have new gas with startron additive in both tanks and also Seafoam in 1 tank and fresh gas. Also running about 45-47:1 mixture, little richer to be safe after recondition. Anyways, I switch tanks and suddenly it chokes to life and I have a great couple of runs, starting out slow then up to full speed/power. Great. Then it starts choking a bit again and dies on going into gear. At this point I'm fairly close the marina. Dies again so when I go to restart...nothing. Starter doesn't turn or anything. Fire up the kicker and back to dock. Pull the cover and the starter's stuck in the flywheel. Pry it loose and fire it up again. This time I notice the fuel line is kinked. Same fuel line boat came with, as are the tanks. Up to the marina shop to get new fuel line and bulb and connector. They had no tanks in. Starts up fine and out I go again.
This time it still seemed a little starved so I gave it a couple of shots from the key choke and it jumped to life. Hmmmm... Anyways, after this I had a great half dozen runs back and forth out in the bay. Feeling pretty good until I ran out of gas in the "good" tank. Switched over to the "bad" tank and there's definitely something up with that tank. It ran but just didn't have the "life" the other tank did. Ok fine, can deal with that. Had it at idle for a minute to tidy up a couple things before I came back in and it died. Went to restart and starter spins but won't engage flywheel. Great. Fire up the kicker and back to dock.
So that was my day. Got home, replaced starter with one from 140 and flushed the kicker and 90 (bay is saltwater). All good. Decided to pull the plugs and test compression. 116-120-118-120 1,2,3,4 respectively. Ok good. Plug one had light tan crusty dry deposits on it though. 2,3,4 plugs all a little black and oily, but identical in appearance. Manual says that it is ash deposits...light brown or white and result from using fuel or oil additives.
Now some questions:
Ok, I had additives in both tanks but why the deposits on cylinder 1 and not the others? Or is this a fuel issue?
I also noticed at idle now there's an occaisional miss. I didn't notice it a various rpm's while running but at idle it's there. I did a link 'n sync but I'm not an expert so maybe I should revisit that. I haven't had a chance to do a WOT timing yet, but that shouldn't affect it idling should it?
While I was on the water at WOT, I couldn't get over 4000rpm. Manual says this motor should be 4500-5500 WOT. I noticed there's a 1/4 inch line from the fuel pump to where the inline gas filter used to be (I took it off and tossed it when I put on the new fuel line but got a male-male hose adapter). In hindsight I should have just run 3/8 straight to the fuel pump. Could this restriction have caused my rpm limit. Or reeds? I'm also going to get 2 new tanks/fittings because even the "good" fuel tank I think leaks air into the line.
I noticed when I put the new line/bulb on, I couldn't fully pump the ball to firm on one and only "almost" firm on the other so I suspect both tanks are faulty.
Oh one more thing. I took the air silencer cover off at home and noticed the inside cover had a coating of oil on it. I'm not sure if this is from bad reeds or just the fact I'm running a bit rich. Also the hose that connects to the lower rear of the housing isn't tight. Very loose so I may tie-wrap it tight later today. Could reeds cause the type of fouling on plug #1 as described above? I could pull the intake off the 140 and see if the reeds are good and will fit the 90 or just get new ones I guess. I haven't had the intake off the 90 to visually see if they're good or not. I had previously assumed the were ok because it runs pretty good when I can keep fuel to it.
Anyways, sorry for the long post but I want to thank in advance everyone on this Johnson forum and Iboats in general. Your advice and knowledge has saved me thousands, literally. I hope I can learn enough to return the favor here...
Cheers.
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