Johnson 60 hp, intermitent 4000rpm

[adam1psu]

Hi,
I've been fighting this problem, thought was fixed trailered boat from pa to fl for vacation now acting up. Motor runs great then after 10 minutes it drops down to 4g rpm at max throttle, compression 135 on all 3 cyl, new fuel filter, fuel lines, pumping ball under load dosent help, it charges at 14v, unpluging charge system makes no difference, tank is vented, has good spark, but unplugging cylinder 3s spark plug wire makes no change in performance when this happens. I replaced the plugs, coils and still same result. I also disconnected the temp sensor and nothing. I found a broken tan/white wire in harness and repaired it...no difference. It is now not intermitent but does all the time. The motor has had its oil pump deleted a as well. I tore apart and cleaned carb no 3...still no diffrence. Reeds on no 3 arent cracked either, I ran motor in dark and witnessed almost no arching. It acts like it's running on slow mode. I am at a loss, please help if you can, I ordered a power pack but don't think it is the issue. Thanks!
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[adam1psu]

Also cylinder 3 has good spark when acting up at 4g, weird also that it has fuel flow into carb, I know this because reeds on cylinder 3 are wet with fuel/oil. Thanks again, any ideas at all I will try.

 

[racerone]

Unplugging the charging system on a running motor is not a good idea.-----But push the key in when motor acts up.----What response do you get when doing that ?

 

[adam1psu]

I will try it, I unplugged the charge system while shut down then started, thanks for the help I will post up tomorow.

 

[F_R]

Water ingestion into #3 ???

 

[adam1psu]

How do I check for water into 3? I did get some white smoke a few trips ago after extended idling in gear, I shut it off to load the boat then while loading......white smoke was noticeable, checked compression a few weeks ago and was good. Thanks for input!

 

[fireman57]

You say that there was almost no arcing at all. Guessing this was at idle on muffs. If you ran it in the dark under a load I bet it increases.The water in number 3 sounds like you are going to put a new head gasket on at minimum.

 

[racerone]

Model # of this motor is ?

 

[adam1psu]

J60PLSSE is the model, I didn't get to try it today but a friend who is a 30 year plus outboard mechanic says it could be my fuel.pump going out too. Im going to check where the pumps vacume plugs into block to look for fuel as an indicator of pump failure. Going to try it in the morning.......also when I said arching I could barely make out very faint barely visible flashes between no 3 boot n plug....I wrapped ceramic insulator on plug either some electrical tape to insulate it from humidity and had the same result with 4000 rpm. Also I will try pushing in the choke....thanks...please stay with me as I try to figure this out.

 

[adam1psu]

Auto spell put extra word" either "in my post....sorry. also this motor has the auto warm up feature....whatever it's called.

 

[Bosunsmate]

An Interesting one this. You said you manually primed the fuel baulb and it didnt fix it so i doubt its the fuel pump.
Try a drop test when you are out, you may find its just one cylinder dropping out.
Also how do the spark plug tips look?

 

[racerone]

Perhaps you should be replacing the plug leads or at least the rubber boots on the sparkplugs.

 

[adam1psu]

The problem is now not intermitent, but 4000 rpm max, yes one cylinder is not combusting, unpluging no 3 plug does not effect it at all....therefore no 3 is dropping out and now not with combustion. It has spark and fuel flow. Spark is strong, new coils, cleaned carb and reeds are wet with fuel
/ oil. Using the choke dosent make a difference either. Unpluging no 1 makes it run worse and unpluging no 1 shuts off the motor......baffling?

 

[adam1psu]

Plugs look good but am pulling them again now, will post up soon.

 

[adam1psu]

I meant unplugging no 2 shuts it down

 

[fireman57]

If you are getting water in number three you can have all the spark you want but water does not combust. Pull the head and take a look.

 

[adam1psu]

Ok, just found potential issue, perfect spark on no 3, while auto warm up is on, as soon as it kicks down to normal idle after 2 min or so spark dissapeared and plug is dead, just called dealer and reclaimed canceled.order for powerpack. This explains why I had spark testing under a load, I was shutting it down to test it and had spark for just 2 minutes every time......hope it works

 

[Bosunsmate]

yep that sounds a possible reason to me. How much for the powerpack?

 

[adam1psu]

$289 on sale from 380...something.... I ordered it a few days ago then said I didn't need it.....now I need it and they still have it. Gulf marine in clearwater fl, great service, small shop.....I will post up results.... thanks for all the suggestions.....

 

[adam1psu]

Also auto warm up lasts exactly 1 minute, I timed it...