Mercury Mark 55E

[bbradb]

Just bought a wooden boat which included this 40 hp motor. Motor appeared to run ok except about an hour into cruise motor suddenly shut down and was difficult to start. May be related to going into idle which may have been to slow. Difficult restart is my concern. where do i start? Thanks. Previous owner stated that he had done a complete rebuild which I was skeptical of since he had no manual?? After finally getting it going again after waiting a bit, it again stalled as we were trying to get it to trailer ranp.

[dave-bernard]

hope it was not over heating. did you do the water pump before you ran it?

[bbradb]

Thanks for reply Dave. unfortunately don’t know what you mean by “did you do the water pump before you ran it”. As I said, just purchased and this was the first time in the water. Seller “assured” us that the motor was just overhauled and good to go. It did start after a bit of a wait but soon failed again after almost making to the boat ramp. Hmmm, perhaps it did overheat. Seller did show us what to me looked like a rubber impellor of some kind that he had replaced. Not sure why he brought that up but as part of that conversation he pointed to where we should see a spurt of water coming out. He called it “pissing”. “watch for that” We did and it seemed to be “pissing”. Sorry bout that. Where do we go from here? I’m not afraid of a mechanical challenge. Never worked on one of these though. Do we need to rig a test tank to do anything? My only outboard project has been a small Honda 4 cycle.

[opposedtwin]

Well, hopefully the “pissing” was adequate to keep the motor from overheating. That’s just water from the lake being used to cool the motor through passageways and then being returned to the lake. The rubber impeller is driven by the drive shaft and pumps the water through the motor with those vanes on it.

Not sure if your seller went through the carburetors or not. It could be a fuel delivery issue.
If you’d like to work on it yourself, you’ll get very good advice here but I also recommend you buy the big mercury manual for motors 1965 and prior. They’re on ebay for 35-55 dollars on average. They’re thorough and will help you understand your motor and it’s issues.

Scott

• This reply was modified 3 years, 10 months ago by opposedtwin.

[opposedtwin]

https://www.ebay.com/itm/Mercury-Outboard-1940-1965-Master-Service-Manual-C-90-25500-8-71-August-1971-/324177530718

1 user thanked author for this post.

bbradb

[billw]

I guess if I were you, I would try to duplicate the condition with the boat on a trailer in the back yard, with the motor running in a barrel. You should be able to tell if it is at least pumping water adequately at idle speed, this way. Also try pumping the fuel line primer bulb gently and see if either carb overflows. My bet is that if it’s not overheating, then it is a fuel issue of some sort. But that’s just an educated guess, sitting at my computer. If you plan to dive into this motor, the factory manual is going to be a basic requirement. If the guy before you worked on it without a manual, well, there’s is your problem….

Long live American manufacturing!

[need2fish]

Make sure the magneto belt is taught and hasn’t skipped a tooth or two (for that, you’d need to redo the timing).

A possibility is the coil has marginal windings — where increased temperature causes a short somewhere in the primary circuit.

[bbradb]

Thank you Bill W. Appreciate your comments. I am encouraged that this motor seems well regarded. Amen to USA manufacturing. Parts hopefully will be available. I will get a .manual immediately. Do I need a Users Manual as well? So can the motor be worked on hanging off transom? Figured I needed to build a rack of some kind.

Here’s a question. Again, first-time boaters of any kind. Fiddling around with the motor control. My son (his boat) was driving or attempting to get the thing going. It’s a 61 Whirlwind 14 footer BTW. Into neutral, etc. for starting. It did start after a couple of tries. Then we noticed that forward/neutral/reverse handle needed to go to the rear in order to move forward. This seemed nonintuitive and odd? Is this surprising or did our guy hook something up backwards? It was very clunky moving between positions as well. Is this normal or does this need work?

[dave-bernard]

m ake sure the vent on the gas tank is open (knob on the gas cap)

[David Bartlett]

How much oil are you mixing in the gas?

David Bartlett
Pine Tree Boating Club Chapter

"I don't fully understand everything I know!"

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