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

[Johnny Ringo !]

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 .

I didn't work on the carb yet, I put it off because I think I'm going to keep it and worked on others that I knew I was going to sell. I usually take them all apart and soak them in asatone for a day except the float needle if it has a rubber tip, they will dissolve as will the plastic or rubber bushing for the main jet, then I blow all passages out with carb cleaner then reassemble the carb with new parts that come in the kits including the Welsh plugs. I also take them out before I soak them.

 

[Johnny Ringo !]

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

It's gone, I sold it in the summer. I had two of them last summer the other one was an 83 Evinrude basically the same motor only newer and it had I believe 105 & 115 lbs. of compression in the cylinders. I was afraid the 72 might not run, but it ran good. Again I read that an outboard will run as long as the compression in the cylinders are all within 10-15 lbs of one another and the compression isn't too low and barring any other problems. I would say the 72 was cutting it close as far as not having enough compression.

 

[Johnny Ringo !]

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 !!

If it has a bad cylinder it should run rough I would think and be sluggish.

 

[Johnny Ringo !]

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.

I am going to rebuild the carb and change the impeller, I have one for it, but not all the parts that I need for the carb I will order a new carb kit. I have to start working on some of the other motors pretty soon to get them ready by spring. I have one Mercury that has no spark, not sure what I will find there. No points. I will have to read up on checking this one out, it could be one or several of things going on. Could be the CDI box, a coil, but no spark in either cylinder, a trigger assembly, Stator assembly ECT.

 

[saltchuckmatt]

Just to address the smoke issue....when working on these motors and it's more important on the larger HP, you must take them out on a boat to clear them out. Motors are designed to work under load so without clearing them expect excess smoke.

 

[Johnny Ringo !]

Just to address the smoke issue....when working on these motors and it's more important on the larger HP, you must take them out on a boat to clear them out. Motors are designed to work under load so without clearing them expect excess smoke.

Yea they can load up quick if you can't open them up for a while now and then.

 

[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 ordered a carb kit and it should be here this week, week of the 21st. I have it apart and soaking in acetone. All except the float needle valve with the rubber tip. Had one dissolve on me. The all metal ones I will soak along with the rest of the carb. I did notice some dirt in the float bowl.

 

[saltchuckmatt]

I ordered a carb kit and it should be here this week, week of the 21st. I have it apart and soaking in acetone. All except the float needle valve with the rubber tip. Had one dissolve on me. The all metal ones I will soak along with the rest of the carb. I did notice some dirt in the float bowl.

Acetone works for you? I use tranny fluid and acetone for rusty bolt penetration but mostly when I clean carbs it's carb cleaner, compressed air and torch tip cleaners. In a worst case scenario, it goes into my ultrasonic cleaner with solvent.

 

[airshot]

Yea be xarefull with Acetone, it can melt/ distort any plastic or rubber parts...better to use carb cleaner and compressed air.

 

[Johnny Ringo !]

Yea be xarefull with Acetone, it can melt/ distort any plastic or rubber parts...better to use carb cleaner and compressed air.

I have had it melt rubber and soft plastic, like the bushings for some of the main jets but not the hard plastic yet, it probably depends on the type of plastic. I saw on you tube a guy using acetone, so I tried it and ruined the tip of a float needle that was rubber and a red main jet bushing got mushy, I believe it was a type of plastic. I just spray them of with carb cleaner now unless they look bad, I prefer the metal Float needles, but you get what's in the kit.
The carb I squirt carb cleaner through all holes and if one seems plugged I use a torch tip cleaner in them. I expect the cleaner to come out somewhere when I spray it into a hole, if not the hole either dead ends or is plugged.

 

[Johnny Ringo !]

Acetone works for you? I use tranny fluid and acetone for rusty bolt penetration but mostly when I clean carbs it's carb cleaner, compressed air and torch tip cleaners. In a worst case scenario, it goes into my ultrasonic cleaner with solvent.

I use torch tip cleaners if when I spray carb cleaner in a hole it doesn't come out anywhere. I do that after the soaking. airshot said be carful with using acetone so I just went out and took the lid off of the container I soak my smaller carbs in to check the plastic that's on it. All is well and it has been in there for two days now, I will leave it there until my carb kit comes.