1989 Johnson 110 hp need help with diagnose dropping cylinder

[86bonito]

Hi all motor was running well at WOT but struggling to idle after two years of sitting.
1989 110 hp bubble back.
Vro disconnected.
I cleaned carbs two hr soak, link and sink put back together all good. After a few times out motor feels like it is dropping a cyl.
Running real rough in no wake zone then try to plane not too much power then a surge of power back to life the motor roars.
Motor will also surge back and forth at mid throttle. New tach not working.
This has happened a few times now on today's Tripp we had to limp home in fear of causing damage.
Got home checked spark yes had spark on all 4. I did not use official 7/16 gauge but cheap H.F. Sealed light up unit.
Then started motor pulled plug wires off one by one heard spark working very hard with a dip in performance.

Anyone have any experience with this?

Also battery is not charging probably rectifier but I thought I should let all problems be known.

Thanks,
Brian

 

[reiddo1]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

Is your oil mix at 50:1? Do the spark plugs all have a light tan even burn appearance?

 

[Ross72]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

I had the same problem with an 89 evinrude 110. Turned out that a plug wire was going bad. Spark tested great and would idle fine. But under load it would kick in and out.

 

[keefallan]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

Check out what Ross72 said. Your resistance should be very near to identical on all the wires. If not throw the culprit out or buy a new set. Also check the coil grounds too. You are already back there working. It'll only take 10 more minutes to unbolt the coils and clean the grounds. Since it's been sitting, when was the last time you've done a compression test?

 

[86bonito]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

Ok,
Yes 50:1, plugs were a little wet but even burn and some carbon.

The plug wires have less than 50 hours on them but will check for resistance.

I will also clean all grounds today.

Compression last checked two years @ 105-110 cold on all 4

Thanks

 

[toddschubert]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

any chance plug wires got reversed? that could cause similar probs.
Rectifier runs tach as well as providing charging. Its probably bad but separate issue. I just changed mine for $24 on iBoats

 

[1FASTLASER]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

First things first. Redo the compression check. Things can happen in 2 years. Carefully inspect fuel system from tank to carbs.

 

[86bonito]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

Compression check 100-105 across the board - getting a little tired.
Pulled all coils off and cleaned off contacts with wire wheel brush.
Contact points were corroded over as well as one of the contacts that the power pack plug hooks up to. I changed that coil out
and took dremel to the rest of the plug ends. Should be getting good contact now.
Started and ran in tub. It ran ok, lots of smoke maybe too much not sure. I may do a decarb tonight.

 

[emdsapmgr]

Re: 1989 Johnson 110 hp need help with diagnose dropping cylinder

Your engine would not run WOT if it had a fuel problem, so it's probably an ignition misfire. If the ignition has a weak component, it will misfire once the engine heats up to normal operating temps. (May run fine when cold.) Warm the engine up and when it starts to act up- do a cyl drop test or use an inductive timing light to check for spark on each plugwire. If you find a misfire, you can test the main ignition components. Coils are not a high failure item, so concentrate on the power pack, stator and timer base. If you are not working from a factory service manual, you can get some excellent ignition troubleshooting information from this website: cdielectronics.com Your tach issue is probably related to a bad combination rectifier/regulator. Does the voltmeter on the boat indicated the battery charges normally after running for 10-15 minutes?