2 hp Johnson: My 2 HP Johnson is a model 2R78R a 1978

[Johnny Ringo !]

I was able to get the lower crankshaft bearing housing off by tapping a small screwdriver into where the gasket is and working my way around it until it finally came off. You have to be careful not to loose the needle bearings out of the top, make sure your in a clean area and put like a sheet down so if any bearings do fall out they shouldn't bounce away. I had 4 top ones come out, but they laid close and were easy to see against a light sheet. The bottom bearings stayed in and I taped the crank fast to the lower housing so it wouldn't come apart and let the bearings drop out. I also put some grease in the top to hold the bearings in and replace the ones that fell out, then I taped paper towel pieces over the ends so they could not fall out while I was working on the piston and cleaning everything up getting ready for the new piston and rings that are coming from Greece. No rings are available it would seem in the united states. My piston is fine but in order to get the rings I had to buy the piston too, and it was the last one they had. This is the 2 hp I had talked about a model 2 R78R

 

[Johnny Ringo !]

Oh I forgot. This 2 HP Johnson is a 1978 model a 2R78R model

 

[racerone]

Rings are shown to be available at your local dealer.----Your location ?

 

[Johnny Ringo !]

Rings are shown to be available at your local dealer.----Your location ?

I am in Lock Haven, Pa I got a piston and rings from Greece, I checked on Ebay and Amazon and all I saw was a single ring it said was for a 2hp and I think a 3hp. All the 2hp Johnsons I checked calls for a two set of rings and all places said they were discontinued. I looked for a year and never saw them available online. Any how I tor the motor down and looked at everything. the piston and rings looked good as did the cylinder walls, but the book still said to hone it to deglaze it, and I did. I had about 65lbs of compression before the teardown and after replacing the rings and putting it back together to the point that I have to put the electronics and carb, and the rest of the top things on yet. I thought I would check the compression. I only replaced the rings because I felt the piston was fine, and it had std. stamped on the top of it and I put std. rings in it. I turned it over with a drill motor and I still only have 65 lbs of compression. I am beside myself right now, not knowing what to do next. The new rings should have raised the compression some, but it didn't. I tapped the hole shut between where the carb and reed valves are and tried it again, no change but I could see the tape moving as I turned the motor over, but the seal didn't break. I have the piston in right I'm sure with the largest side of the piston dome facing the intake side of the cylinder wall. I hate the thoughts of tearing it all apart again, I had a time with those needle bearings.

 

[racerone]

I believe at 65 PSI it was in good condition and no need to tear this motor down.

 

[Crosbyman]

just run it see how it goes .

can't get much simpler than a one piston 2hp.
I have never taken an engine appart and my 9.5hp runs perfectly well at 65psi

 

[racerone]

Agreed.----And a local dealer would / should help you find those rings.----No need to resort to getting stuff from overseas in my opinion.-----I have new rings on hand for one of these simple projects.

 

[airshot]

These little motors don't gave much compression, I have the 2.2 hp Merc single and it pulls very easy. Wouldn't want a hard to pull start motor on the back of a canoe !!

 

[Johnny Ringo !]

I believe at 65 PSI it was in good condition and no need to tear this motor down.

These little motors don't gave much compression, I have the 2.2 hp Merc single and it pulls very easy. Wouldn't want a hard to pull start motor on the back of a canoe !!

I believe at 65 PSI it was in good condition and no need to tear this motor down.

 

[Johnny Ringo !]

I read some place that they like about 100lbs of compression and that is why I replaced the rings when I only got 60-65 lbs of compression. It may have been bad information. But when I tried starting it before the teardown last year with the pull starter it didn't try to start, but turning it over faster with a drill motor it kept trying to start then finally did, but it would not rev up and would stall when I pulled the drill motor off. I left the compression tester hooked up yesterday and today when I went to load my woodstove I noticed the tester still read 65lbs as it did yesterday. So that tells me the rings must not be letting blow-by. Perhaps the carb needs cleaned. I got this motor last year in a two motor deal and both motors were said to run. The other one was a 1983 9.9 HP Johnson I usually always replace the impellers and either clean or rebuilt the carbs on all motors I buy. I do that automatically but I didn't do it to this 2hp yet. I am 71 and have been doing this as a winter to spring hobby. I also paint the ones that need it, then resell them. I redone I think it was a mid 90's Gamefisher 9.9 hp made by Mercury for Chrysler's Fource outboards.
. The seller said it would run, but stalled out when put into gear. I figured it was probably just the carb until I checked the compression the top was around 100 and the bottom was O ! I thought rings or piston, but it ended up being a blown head gasket as you can see in the first pic. All of the red was faded out and I hand painted the red back on, not perfect but close. What do you think I should do about the 2hp Johnson ? Thanks for your help

 

[racerone]

The tester may have shown 65 PSI but there was zero pressure in the cylinder.

 

[airshot]

I have never found the little 2-3 hp motors to have anywhere near 100 # of compression. Up in the 10-15 hp range yes and up as the hp gets higher and the cylinders get bigger..

 

[Crosbyman]

see post #6

 

[Johnny Ringo !]

I have never found the little 2-3 hp motors to have anywhere near 100 # of compression. Up in the 10-15 hp range yes and up as the hp gets higher and the cylinders get bigger..

So why didn't it keep running last year ? My next bet would be the carb, how about you? Thanks for your input. It all makes sense now why there wasn't much change in the compression from before to after teardown. I learn by my mistakes or by tearing something apart for the first time. And for some reason I gained another 5 lbs of compression today without squirting anything into the motor. It got to 70 lbs today. What will happen if I get it running, will the compression raise any or drop or stay the same ?

 

[Johnny Ringo !]

just run it see how it goes .

can't get much simpler than a one piston 2hp.
I have never taken an engine appart and my 9.5hp runs perfectly well at 65psi

I don't think the two cylinders need as much because the pistons are helping each other out. I bought a 1972 25hp from a guy that said it ran, it didn't it had a tiller on it but was set-up for remote operation. I changed it back to tiller operation. It had no spark at all I filed the two sets of points and replaced the condensers and had spark. It ran after that, but that motor was an anniversary motor and it only had about 60lbs in one cylinder and 65 lbs in the other one and it ran great. The first guy that looked at it said it smoked too much and backed out of the deal. I do put a little bit more oil in the fuel if the motor has set a year or more, This one sat for at least several years but I didn't think the smoke was that alarming. It also had electric start. I had to get a solenoid a start and stop button and install them. I have learned a lot the three years I have been working on outboards. I can usually find a video showing me how to do most things.

 

[airshot]

Hard to say, all depends on what is causing the change in compression.. Thought you already went thru the carb ?? If not then a definete rebuild is in order, get a factory rebuild kit so you have all new gaskets and the settings needed to get it going. Have you checked the spark ! Jump a 1\4" gap ?

 

[airshot]

I don't think the two cylinders need as much because the pistons are helping each other out. I bought a 25hp from a guy that said it ran, it didn't it had a tiller on it but was set-up for remote operation. I changed it back to tiller operation. It had no spark at all I filed the two sets of points and replaced the condensers and had spark. It ran after that, but that motor was an anniversary motor and it only had about 60lbs in one cylinder and 65 lbs in the other one and it ran great. The first guy that looked at it said it smoked too much and backed out of the deal. I do put a little bit more oil in the fuel if the motor has set a year or more, but I didn't think the smoke was that alarming. It also had electric start. I had to get a solenoid a start and stop button and install them. I have learned a lot the three years I have been working on outboards. I can usually find a video showing me how to do most things.

What they are designed to do and what you can or might get away with is not always the same. I have saw many motors run with bad cylinders, but that doesn' t mean they run correctly !!

 

[Crosbyman]

when you choke the engine to start it and put the throttle at start or slow the fuel is sucked up into the top idle drip chamber then inhaled in the crankcase.

did you take the carb appart clean the top chamber , check passage at the needle tip and.... the side channel leading from the bowl to the top.

the side channel very narrow and must be clean .

 

[Johnny Ringo !]

Hard to say, all depends on what is causing the change in compression.. Thought you already went thru the carb ?? If not then a definete rebuild is in order, get a factory rebuild kit so you have all new gaskets and the settings needed to get it going. Have you checked the spark ! Jump a 1\4" gap ?

I checked the spark, but don't remember how much gap it was shooting across. I didn't do the carb when I bought it as I usually do because I am thinking about keeping it to troll for crappies with and just put it off till later. It turns over easy and it is easy to carry. I do have two or three small Mercury outboards that I haven't checked yet I think they are 4 hp ones and I have an 18hp Mercury and a couple of 9.9 Mercury's and I believe two 6hp Johnsons I have to work on now that hunting season is over.

 

[racerone]

I think you need to check your compression tester.----Or borrow / rent one and check compression on that 25 HP motor.