1967 Johnson Low Compression

[linxlvr]

Hi all. I have a 1967 Johnson 9.5 that has 75 psi on one cyl., 65 psi on the other cyl. I realize this is low, but I am talking a cold motor that hasn't been run in 6 months.

It was handed to me as a can't start kind of project. I am good w/ 4 stroke engine mechanics, so I was hoping w/ the assistance of this board and a Seloc manual, I can get through it. It's only my second outboard, the other being a 10 hp 1958 seahorse. That just ended up being a combination of several carb and ignition problems.

So I am wondering, how low is low on a won't start?

TY all in advance.
--
dw

 

[Solittle]

Re: 1967 Johnson Low Compression

I wouldn't worry about the compression just yet. See if you can get it running and then do a decarb and follow with a retest of the compression. You might try a different compression tester in case the one you used tends to read low. Compression will be O.K. if the cylinders are within 10% of each other.

 

[JB]

Re: 1967 Johnson Low Compression

First, go to Engine FAQs and do the "Outboard won't start" troubleshooting.

Once she is running do a decarb, then a new compression test.

You probably have a jewel that just needs a bit of cleaning up.

 

[linxlvr]

Re: 1967 Johnson Low Compression

TY both of you. Will look into it this weekend and post questions / results.
Thanks again.
--
dw

 

[yamadirt426]

Re: 1967 Johnson Low Compression

just wondering how your motor is coming. I just picked up a running 73johnson 9.5 and with my comp test I got about 64 on the top and 74 on the bottom. Its just it smokes alot. I'm gonna clean the carb and take a look today.

 

[tashasdaddy]

Re: 1967 Johnson Low Compression

it probably has never had a decarb, smoke could be carbon burning off.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards recheck compression.

 

[yamadirt426]

Re: 1967 Johnson Low Compression

it probably has never had a decarb, smoke could be carbon burning off.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards recheck compression.

ok This is what I will do as soon as I can find that product up here in canada. I still have not gone to a boat store. Just to lordco autoparts and canadian tire and they don't carry seafoam. I just cleaned the carb and it looked nice and clean as well as the intake. So I think it has been done recently. It smoked for a bit but that seem to calm done allthough did not stop completely. All this work done in a barrel so I hope it just needs some seafoam and a good run. Can I get this product in canada?

 

[HighTrim]

Re: 1967 Johnson Low Compression

Yamadirt, where exactly are you located?

I am in Ontario, and too had never heard about Seafoam until I joined this forum. Prior to that, had used BRP's Carbon Guard, along with running XD 50 synthetic oil. I did run down to Buffalo to grab a couple cans of Seafoam to try it out, and it did work superbly. The Carbon Guard you can purchase from any Jonnie/Rude dealer in Canada, however, I have never used it for a concentrated de carb procedure, strictly maintainence de carbing. Others may be able to tell you if they have personally tried. I have been told that certain NAPA's do carry Seafoam, there may be one in your area.

 

[linxlvr]

Re: 1967 Johnson Low Compression

just wondering how your motor is coming. I just picked up a running 73johnson 9.5 and with my comp test I got about 64 on the top and 74 on the bottom. Its just it smokes alot. I'm gonna clean the carb and take a look today.

Actually, I had car problems with one of my cars, so since it was February the outboard got side lined real fast. I started to go through the list for no start and can tell you it has excellent spark, both wires. Probably carb issues, though on my QD19 I had plug wire leads being problematic when throttle was at a certain setting. Suppose it could wind up there. Will be sure to post update. When I get to it, probably next weekend.
--
dw

 

[yamadirt426]

Re: 1967 Johnson Low Compression

Actually, I had car problems with one of my cars, so since it was February the outboard got side lined real fast. I started to go through the list for no start and can tell you it has excellent spark, both wires. Probably carb issues, though on my QD19 I had plug wire leads being problematic when throttle was at a certain setting. Suppose it could wind up there. Will be sure to post update. When I get to it, probably next weekend.
--
dw

Cool. Lets us know.

I'm in Van B.C. Canada. We have lots of napa auto parts here so I will go there tomo and see what I can find.

 

[Evinrude Boater]

Re: 1967 Johnson Low Compression

Napa carry many boat parts too. I get Sea-Foam from a store in a little inland store so it shouldn't be much of a problem in Vancouver.
You really need to get the boat on the water and run it hard to clean it out. In a barrel it will only do so much.
You might even consider taking the head off so you can inspect the cylinder walls for scoring and scrape some of the carbon off.

 

[linxlvr]

Re: 1967 Johnson Low Compression

Float was sticking in carb, also threads weren't so great on bottom spark plug hole, did a helicoil there. Seems to run quite well in a barrel, will have to take it out to warm it up well and adjust mix, but TY all for your help, and it certainly did not need rings.
--
dw

 

[wavrider]

Re: 1967 Johnson Low Compression

Sounds great glad you got the engine going. The smoke is nothing unusual on a two stroke just waking up.

Napa here in the states does carry the seafoam, and the deep creep also.

Sea foam mixes in the gas and runs that way.

It is best way to de-carb as it cleans everything in the engine.

I also go one step further and spray deep creep into the cylinders after it warms up running the sea foam in the gas and reinstall plugs. Turn the flywheel a few with spark plug wires off and let it set 15 minutes.

Pull the plugs and pull the start rope a few times to clear the excess deep creep out of the cylinders. Reinstall plugs and fire it up. going to smoke like a banshee.

 

[samo_ott]

Re: 1967 Johnson Low Compression

Also a head gasket might help the compression but do the decarb first.

Like HighTrim, I also had never heard of Seafoam/DeepCreep until joining this board and now I use it for everything (even drying my wires on my Jeep on a wet day!) I get it at NAPA in Ottawa and at a little no name auto parts store near my cottage in rural Quebec. So look around. It's @$12 a tin at home and that reminds me, as I'm in Florida now, to go get some as I hear it's like $6 a tin down here or something like that. There's an AutoZone down the street so I'll go take a look.

 

[wavrider]

Re: 1967 Johnson Low Compression

Yes I think auto zone has it and also advanced auto for around 7$, napa has it for around 8$ hee in florida.