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1956 Johnson Seahorse 15hp

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hal5778

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Hello I have a 1956 Johnson Seahorse 15hp that I have finally gotten to run. The issue I have is although I have used the TWC 3 at a 25:1 ratio the motor seems to be smoking way too much. It even has oil dripping from the lower cowling. I can get the motor to contiguously run (a bit rough) at an rpm above idle but as soon as I turn throttle to an idle the motor stalls. I have installed new plugs Champion J6C and wires,coils and removed and cleaned the carb. I have preset the high and low speed adjustments at 1 1/2 turns out but this issue continues to remain. I am running the motor in a water barrel and there seems to be a good bit of oil in the barrel water as well. Any help with this issue would be greatly appreciated I am so close to having this motor water ready but yet so far away
 
The problem is that the adjustable slow & high needle valves at 1-1/2 turn out are at the initial setting whereas they need to be adjusted properly from that point.... as follows:
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(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason `to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
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Thank you Joe I will attempt your directions and let you know how it works out this was my dads motor and would like to put it back in use on his old boat as well
 
1. Smoke is normal
2. Oil in the barrel is normal
3. One and a half turns on the high speed is way, way, way too much. 3/4 turn prpbably will need to be leaned out in final adjutment.
4. Get it out of that barrel and onto a boat on the lake, then get it properly adjusted and you will find it is a whole different motor.
 
fdrgator said:
1. Smoke is normal
2. Oil in the barrel is normal
3. One and a half turns on the high speed is way, way, way too much. 3/4 turn prpbably will need to be leaned out in final adjutment.
4. Get it out of that barrel and onto a boat on the lake, then get it properly adjusted and you will find it is a whole different motor.
Click to expand...



Thank you I will try the new position for the high speed and then put on boat hopefully for a final adjustment. Do you think that the change in the high speed adjustment will correct the idle issue
 
Thank you I will try the new position for the high speed and then put on boat hopefully for a final adjustment. Do you think that the change in the high speed adjustment will correct the idle issue
 
You also need to adjust the low speed needle to compensate for fuel and local atmospheric conditions.-----The factory / book settings are only to get the motor to start and keep running.
 
Thanks Joe and all who responded I will let you know how things work out. On a different note I also have a 1957 10hp Johnson I will be working on after the 15 is complete and I am looking for at this point a throttle lever selection band (tiller has a white handle) and also I need what appears to be a nylon keyway which is located at the bottom of the vertical arm going from the tiller handle gears to the pivot arm on the top if anyone knows where I can obtain these please let me know. Thanks
 
The nylon pin is part number 304155. The throttle band was sold under a bunch of numbers, only difference in color, etc. Two numbers were 203260 and 303110. May be available here at iboats from their OEM parts source.

OR go to Antique Outboard Club's website a post a want ad. Those parts are a likely find in lots of goody boxes
 
Try Tim's outboard in Hackensack Minnesota at 218-682-2331. Also try opening cowling to supply fresh air whenever tuning in a barrel. Even use an electric fan to introduce fresh air
Or......do it out on the lake.....in the open air.
 
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