'93 Johnson 40

[Hooli]

Just got a 93 Tracker with a Johnson 40, hadn't run in over a year. Cleared complete fuel system and replaced with fresh, plugs are fine. Fired up and ran about 8 miles upriver beautifully until I started hearing warning horns (don't know what they were, didn't count). Cycled the key, horns went out. The temp of the motor was fine, it has plenty of water pressure, if anythihng the head feelt cooler than I would have expected. Anyway, about a mile and a half back the motor starts losing power and just dies. No horns. Wait a few secs and fire it up and go again. This goes on and on every 1/4 to half mile till I finally run the battery down and it won't crank fast enough anymore. My fears are/were lack of oil and that I finally scored the pistons. When I got home, I could easily turn the motor by hand and obviously felt TDC on the compression stroke, so my fears were lessened a bit (I did not try this on the water, wish I would have!) I put the battery on charge and went and bought a Clymer, the only book I can find locally. I have a few questions: first what would this appear to be a symptom of? Second, what should the compression on each cylinder be, I have not found it in the book yet. Any help would be greatly appreciated . . .

 

[woody66912]

Re: '93 Johnson 40

110/120 depending on your gauge.if your plugs have a grayish look you shes toast.

 

[tashasdaddy]

Re: '93 Johnson 40

compression is not a published item, as guages are so different. post what you get. it sounds like your thermostats are not opening. just because you have the tale tell stream, does not mean the motor is cooling. what alarm did you get.
J/E Alarms

low oil alarm is a beep every 30 seconds. beep......................beep...................

no oil alarm is a beep every 1/2 second or so.beep,beep,beep

overheat alarm is a constant beep.beeeeeeeeeeeeeeeeeeeeeep

 

[Hooli]

Re: '93 Johnson 40

It was a bunch of beeps. I'm going to do a compression check and look at the plugs, I'll let you know . . .

Thanks guys.

 

[tashasdaddy]

Re: '93 Johnson 40

did you disconnect oil like at pump, and prime oil line, till you got straight oil, no air?

 

[Hooli]

Re: '93 Johnson 40

No I didn't prime the oil line, I ran the motor with a flusher in my driveway for 20 mins and saw smoke (albeit not much) so I didn't figure anything was wrong. Well, I just pulled the plugs and they are grey. The bottom one worse than the top. What's the grey from? The top cylinder has 135-138 psi and the bottom has 25-30. So what's the play? Is this a real tough job with typical tools or does it require a shop? I am a competent enough mechanic on 2 and 4 stroke motorcycles and cars, but from some reason marine engines have intimidated me . . .

What am I looking at? Sleeve and piston, or rod and crank too?

 

[ottertail]

Re: '93 Johnson 40

It is hard to say what you are looking at from this point. The engine will need to be disassembled to determine the damage. The enginge can be bored to oversized depending on the damage. The cause of the damage will have to be determined. don't jump to the conculsion it was the VRO pump. If it was lack of oil it would not be just on the bottom cylinder. If it is one cylinder damage only look real hard at your bottom carb. It is not hard to rebuild. Pay attention to details and you will be fine. As long as you are going in I would freshen up both cylinders and bearings.

 

[tashasdaddy]

Re: '93 Johnson 40

pull the head, and exhaust cover, this will give you a view. pull head first, could be head gasket blown, from overheating, but i doubt it. if there are bits of metal, and scoring, then pull the exhaust cover, and see how bad it is. could be just have the the jug milled oversized. who know till you one it up.

 

[Hooli]

Re: '93 Johnson 40

We aren't talking a few hundred $$, are we? What is a powerhead? What does it include? The links above take me to a rebuilt powerhead exchange for $1300. Is this more like the $$ I am looking at?

 

[ottertail]

Re: '93 Johnson 40

Unfortunatly you are correct. Rebuilding is expensive,

 

[tashasdaddy]

Re: '93 Johnson 40

DO not jump the gun. trouble shooting first. it is a parts motor at present. but could be easy or hard fix. no one knows until you do as suggested. the powerhead is the engine part of the motor.

 

[Hooli]

Re: '93 Johnson 40

Ok, I guess I'll begin a teardown. Forgive my ignorance, but when you say take off the head and then the exhaust cover, are you suggesting do that while on the boat, or should I remove the whole powerhead first? Thanks. Shoulda remembered from my last boat that the definition of a "boat" is: A hole in the water you pour money in to.

 

[Hooli]

Re: '93 Johnson 40

That wasn't very hard. It confirmed damage in the bottom cylinder, lots of light scoring. Nothing deep or nasty, but very dry and definitely scored. The top cylinder looks fine, no scoring whatsoever, and still very smooth. Dry, but smooth. I removed the exhaust cover, but not sure what that would show. That appears to be a water passageway? I am going to try and post pics of both.

So, obviously the powerhead needs to come apart, but what do I need to do? Can it be sleeved? Bored oversize? What are my options?

Also, I was running leaded gas (100LL AVGAS). Could that have been an issue? It appears to have been only one cylinder and I am still stuck with figuring out what happened so it won't happen again.

 

[tashasdaddy]

Re: '93 Johnson 40

looks like boring and piston and rings. it is going to have to be torn down. you need the Johnson manual if you are going to do it. lost of pictures, and keep pairs as pairs. and mark bearing where they go. you can get the correct manual number here, http://www.outboardbooks.com/ you can buy there, or try ebay. another possible reason, is the lower carb could have been dirty, not delivering enough fuel/oil.

 

[Hooli]

Re: '93 Johnson 40

Ok, thanks. Last few questions and I will leave everyone alone. First, is it reasonable to expect that the lower end (rods and crank) were spared? I know I'll need to check tolerances, but curious to know. Second, should I do anything with the top piston? At least replace the rings? Third, what about all the bearings, should I replace them? If I end up doing ALL that, why not just buy a rebuilt powerhead?

Also, Ken Cook Co. shows a Parts Catalog AND a Parts Catalog Set, AND a Service Manual AND a Service Manual Set. Anyone know what the differences are?