1976 Johnson 85 hp idling issue again need help

[tom5410]

Joe the boat was given to me after sitting for 5 years in a slip in the air, I haven't had it in the water yet just on muffs working out the kinks, replacing seat, checking wiring, replaced carpet. but a few months ago it ran great after getting spark back and rebuilding carb twice. While my brother was here we were going to take it to the lake but I wanted to start it on muffs first to make sure it was running like before and it wasn't, replaced all four coils two had cracks and the other two above 1 and 3 looked like they had been melted a little so it could of been overheated before I got it. The cylinders look good, pistons have some carbon on them, two and four cover looks pretty good but 1 and 3 cover has a lot of salt build up between cover gaskets, I'm guessing it salt, looks like a lot of white compacted powder. No scratches on cylinder walls. water passages are pretty clean, not a lot of build up.

 

[tom5410]

One of the first thing that I did was change out oil and water pump

 

[Joe Reeves]

Quote edited somewhat so I can view portions at a glance.

Boat was given to me after sitting for 5 years.... I haven't had it in the water yet just on muffs.... checking wiring,... A few months ago it ran great after getting spark back and rebuilding carburetor....

While my brother was here we were going to take it to the lake. I wanted to start it on muffs first to assure it ran like before. It wasn't,... Replaced all four coils as two had cracks and the other two above 1 and 3 looked like they had melted a little.... It could of been overheated before I got it.

The cylinders look good, pistons have some carbon on them, two and four cover looks pretty good but 1 and 3 cover has a lot of salt build up between cover gaskets, I'm guessing it salt, looks like a lot of white compacted powder. No scratches on cylinder walls. water passages are pretty clean, not a lot of build up.

Before you get into the following.... Compression relates to the speed in which the engine cranks over..... If you have a slow cranking engine (weak starter, bad battery, poor connections, whatever) that will result in poor compression readings and no ignition.

1976 85hp Johnson

Ignoring the compression readings momentarily..... I'm under the impression that the engine has no spark also? If so:

The engine must crank over at least 300 rpms in order for the stator to energize the powerpack capacitor.
Remove all spark plugs.
Rig a spark tester so that the spark must jump a 7/16" gap... the gap is important!
If no spark... and the key is in the ON position, do the following:
Remove what should be a black/yellow wire... regardless of color, it will be the first wire on the port side of the powerpack on the bottom row.
NOTE: Standing in back of the engine, facing the spark plugs... Port is Left... Starboard is Right (some have a problem with that).
Re-test for spark... Do you now have spark? If so, replace the ignition switch.

Let us know what you find.

 

[tom5410]

I have spark but when I first got the boat it didn't. it runs now but the popping at idle is what I'm trying to solve, I don't know if its electrical are fuel related, last time it was the carbs, this time I have been checking everything, fresh fuel, rebuild carbs again and replaced all four ignition coils I also checked timing per sticky. I just don't know what to ck next, with the white powder stuff on starboard side on 1and 3 cover I don't know if that is salt are from over heat the motor. I have found out that its going to be hard to find head gaskets 318662 now.

 

[EchoNovember]

That white powder could be aluminum oxide, which occurs when the aluminum parts start corroding.

 

[tom5410]

Thanks EchoNovember I did find it on both cover.

 

[ondarvr]

It's not common for a motor to run with compression numbers that low, and popping at idle can be from bad rings or piston damage.

​If the cylinder walls actually look that good and the rings aren't broken, I'd try to decarb the motor before doing anything else, if the rings are stuck this may free them up.

But this could still be from a gauge not reading correctly, or something similar.

 

[oldboat1]

Any way you can test it with the l.u. submersed, and see what you come up with? You would still be able to pick up a miss at idle if there is one. (Good idea to measure spark as suggested -- standard test anyway, even if having no symptoms.)

Use the oem recommended plugs, btw -- probably L77JC4 gapped at .030, but check.

(If you can rent or borrow another compression tester, I would do that -- skeptical about your current readings.)

 

[EchoNovember]

I have spark but when I first got the boat it didn't. it runs now but the popping at idle is what I'm trying to solve, I don't know if its electrical are fuel related, last time it was the carbs, this time I have been checking everything, fresh fuel, rebuild carbs again and replaced all four ignition coils I also checked timing per sticky. I just don't know what to ck next, with the white powder stuff on starboard side on 1and 3 cover I don't know if that is salt are from over heat the motor. I have found out that its going to be hard to find head gaskets 318662 now.

Found one for you.

http://shop.tsmperformance.net/Head...9-79-Replaces31866230604818-2959-TS-34030.htm

 

[tom5410]

I will decarb the engine and ck the piston rings, I have ordered gaskets and will ck compression with different tester. I do have the recommended plugs in from reading on forum , I agree it may be the readings r off, I'll get everything cleaned up and back together and retest with submerged lower unit, I really appreciate all the help.

 

[EchoNovember]

That's what we're here for. Lots of great guys on this forum, lots of knowledge, and you can learn a lot really fast. See my join date? I've been boating a month longer than that. I've been fixing my own car, motorcycle, whatever, engines for years, but the boat related stuff these guys have been cramming into my head for the last couple of months.

Read other threads, learn a lot more than you would have ever expected to.

 

[tom5410]

This site is great, I get on here sometime just to read what is going on with different motors. I got mine back together and recheck with a different compression tester after decarb engine, No 1,2,3, are at 120 psi, #4 was at 118, still have the misfire, I did notice that I had spark plugs gap at 30 and were suppose to be 40 by the book and when I got it started it warmed up 5 to 10 sec. before it started misfiring if that make any difference. Any idea on what I should ck for that might be causing the misfire. It has fresh fuel and new batteries. Joe was right on the compression tester, the only plastic I have seen kind of melted were the 2 ignition coils above 1 and 3 and I did replace them, the jel that were in all the coils was really soft also.

 

[racerone]

Run with a timing light and see if there is an ignition miss.----Test on all 4 leads.

 

[tom5410]

racerone one thing I just notice was a arc on #2 plug wire to spark plug, does that indicate a bad ground? redid the end of plug wire but no change still arcing. I do have motor in tub also.

 

[racerone]

Replace the sparkplug boot !----Better yet replace all 4 of them.

 

[tom5410]

OK got that done, replaced plug wire boots and no more arcing , took a little bit to get it started, had to put fuel down the air breather and finally started, ck spark on all cylinders with spark checker and timing light for dark spots and consistency, all good there, My thinking it is a fuel problem, seem like a few months ago I had the same problem and rebuilt the carb two r three times before it cleared up, so when I started it up again it the same problem even though I have cleaned the carbs twice in the last week with no change, I have to keep idle at 1000, anything below it will die, any idea is greatly appreciated.

 

[oldboat1]

No missing detected, though, while running with the l.u. submerged, new boots? I believe you should be looking for idle at about 700 rpm in the lake (+/-). It would be higher on muffs.

Not real familiar with your carbs, but think you have a couple of idle orifices in each. Think I would soak the tops with jets in place, then go back to them with carb spray (using plastic wand) and a piece of mono or soft wire.

 

[tom5410]

Will try that oldboat1, I have taken them off so often now its no big thing, I'm ready to try anything to get this running right Thanks

 

[tom5410]

Oh and yes it still missing, that is what kills it like it hits something and dies, but will crank right back up with the miss there.

 

[racerone]

If you have cleaned the carburetors 6 times and no change it is not a carburetor issue !!-----Do more trouble shooting.---Possible throttle is opening too soon.----Testing is the path forward here.