New to me 1957 Johnson 18hp

[droolbot]

Picked up this motor yesterday, got it home, put it in the barrel....4 pulls later it was running! Kicking and sputtering, but running. Started it on 50:1 mix as I was so excited I did not think to check what this model actually should be, which is 24:1. Would this contribute to the kicking and sputtering? Also, smoked A LOT...looked like smoke coming from under hood. Looks like I had some fu3l running out from under, and water was very oily when I stopped playing with it. Have not taken off hood yet to look, but decided I would post here and see if there are any not so obvious places to look, and if it is ok to run without hood. Other thing I noticed was the slow running fuel mixture knob spins completely around. Should this only turn in the range specified? Thanks for any help in advance! Very excited about this engine, as it is a much better match for my 56 boat than my other motor!

 

[droolbot]

Answered my question on low speed mix control. Hood pushed plate back so not hitting notches. Yikes..dont know how many revolutions i turned it while trying to figure it out...

 

[hardwater fisherman]

I dont think starting and running on 50to1 for a short time will do much damage. Just hope the previous owners ran it with the right mixture.

 

[droolbot]

Thank you for that info. Now for my biggest concerns...is smoke supposed to come out from under the hood on these? Also, is it normal to have quite oily water after running for a few minutes in the barrel? My experience with boat motors is veey limited, and have never been around one this old.

 

[hardwater fisherman]

Oil in the barrel is normal. Where exactly is the smoke coming from under the hood?

 

[bwkre]

Do you mean "under the hood" as in from within the cover / hood or actually under the unit. I doubt it would run very well if the smoke was from within as it would also be sucked into the carb. Probably from below the motor cover, could be hard to see running in a barrel. You can run the motor with the cover off and it will probably even run better with easier access to oxygen. Smoke from close quarters of a barrel tends to get inhaled by the carb especially with the cover on. Might make it easier to spot where the exhaust is coming from.

 

[droolbot]

I am going to cut my barrel down this weekend so I can fit it under while engine is on the stand. Hpefully with a little space between the head and the barrel I will be able to see something running with hood off. I read another post that stated to adjust the idle mix when out on the lake. That makes sense now! Carb would have a hard time functioning in the barrel environment.

So oil in the water is normal? I was expecting some, but was very shocked when I looked down and the water was completely black. May be a case of a little looking like a lot, but wow, glad I have an electric motor for trolling as I am thinking they would be looking for the leaking ship from the slick I would be creating after a couple hours.

 

[pro-crastinator]

"So oil in the water is normal? I was expecting some, but was very shocked when I looked down and the water was completely black. May be a case of a little looking like a lot, but wow, glad I have an electric motor for trolling as I am thinking they would be looking for the leaking ship from the slick I would be creating after a couple hours."

Fear not. Perfectly normal. You will be amazed when it gets on the lake and runs at normal speed - zero smoke.
My 56 with 16:1 mix goobers up the barrel as well. Get it on the lake - everything changes.

 

[64osby]

Great motor you have there and a great vintage.

I've fixed up a few of these and they run great.

Before you go out on a voyage you should go through it.

Inspect the coils, check compression, rebuild the carbs, check the LU fluid and replace the impeller.

Replace or repair anything that requires it.

If you do the above you will have a motor that will last another 50 years.

 

[HighTrim]

Your issue is with the low speed needle. Remove the cowl. Your packing nut has loosened off. It is the 7/16" nut, behind the upper dial. Once you set your needle, it prevents it from bouncing around like you are witnessing now. Your mix is likely VERY RICH, causing the excess smoke and poor idle. However, as mentioned, it will smoke more than normal while in the barrel.

Turn the low speed needle in, clockwise, gently, until it seats (stops). Now back it out 1 1/2 turns. Tighten up the 7/16 nut. Now gently turn the high speed needle in clockwise, until it seats, then back it out 3/4 of a turn. Tighten up the packing nut.

When on the water , go wide open throttle. Slowly, giving the motor time to respond, turn the high speed needle in clockwise, until it runs poor or backfires, then back it off 1/4 turn.

Go down to an idle, and do the same with the low speed needle. Thread in, or clockwise, until you hear it lean sneeze, mildly backfire. Back it out 1/4 turn and lock that one down.

YOu are good to go!

 

[Vintage Boat Guy]

As stated your low speed idle needs adjustment, you may also want to check the needle itself for wear. If exhaust is coming from under the hood you may need to tighten a few screws or check that your exhaust is not plugged up.

 

[boobie]

Edit.....

 

[Greg O.]

When running a motor in a barrel, I like to run a fan blowing the smoke away from the motor. If the motor is suckling in dirty air, it smokes even worse, ito just keeps compounding.