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Johnson 115Hp V4 timing/carbs synchronising

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gkm24

Regular Contributor
I have a Johnson 115Hp V4 outboard which I am pretty sure is a 1988 although it does not have its ID tag. It is a premix engine and has not had a VRO pump taken off it. I have ordered parts for it in the past for a 1988 which have fitted but maybe I have been lucky. The welch plug has some numbers on it but i'm not sure if that really can ID the model, those numbers are C0400119.
Can anyone please advise me on the timing/carb sync set up as it is currently only revving to 3500 with the throttle lever in the full speed position. The carbs are not full open at this setting and i'm not sure if they are supposed to be. I am a motor mechanic by trade so am capable of the adjustment/alignment if I have the data. I'm not sure of the size prop on the boat as I can't see any figures although the prop shows signs of a repair at some time. The boat weight approx 700KGS and at 3500rpm it is travelling at 30mph. The last bit is just in case it helps.
Thanks for any help. I would put it into a shop to have it done but here in the UK, finding a decent outboard mech is a very rare thing and I find that if I do the job myself, I know it will be done right.
 
Make sure that you have proper compression (100+ psi), and blue spark on all cylinders that will jump a 7/16" gap.

With the throttle roller NOT touching the metal cam..... the linkages between the carburetors should be such that all throttle butterlies are full open and absolutely closed shut at the same time.

The scribe mark on the metal cam should be dead center with the throttle roller when throttle butterflies just start to open.

Yes, of course the throttle butterflies should be wide open (horizontal) when at full throttle.
 
Thanks for the info Joe.
I will check that out.
Im pretty sure that the butterflies are synchronised.
At idle, the carbs are closed and as you move the lever forward, the timing advances to the point where they reach the stop. The carbs at this point are approx one quarter open. I will try to get some pics of the engine in the hope that someone may be able to let me know if it looks like a 1988 model.
 
It normal for the carburetors to be only partially open when the timer base hits the full spark advance stop. It is then that all rpm function is carburetor operated. Don't be concerned about that.

If at full throttle, the butterflies are not fully open, disconnect the throttle cable from the engine and push the engine's linkage (where the throttle cable was connected) by hand as far as it will go. If the butterflies are now fully open, then obviously a throttle cable problem exists (adjustement?).
 
The timer base hits the full spark advance stop and the carbs are only a quarter open even with the cable disconnected and the lever operated by hand as far as it will go. Definately some adjustment issues with the linkage I think.
 
A problem is that neither Evinrude or Johnson manufactured a 115hp in 1988 so we/re going to need to pinpoint exactly what you have... or get very close to it.

There should be a model ID plate on theoutside of the port transom bracket... OR... a heavy duty decal at the inside top portion of the steering swivel bracket, facing the long exhaust housing... OR... a quarter size core plug that looks like a freeze out plug on the powerhead... all of which should have the sserial and model number imprinted upon it.

Other than that, we'll need an assortment of pictures to determine what you have.

On most of the older V4 engines, there is a threaded rod attached to the vertical throttle arm of the engine that has a nylon clevis attached to the threaded end which controls the metal cam. Exactly where that nylon connector is set on the threads is governed by the idle timing.... 2,3,4 degrees, somewhere in there. That idle degree setting is set via a timing light when the scribe mark on the metal cam is dead center with the throttle roller.

If anyone has tinkered with the location of that nylon clevis, it'll require resetting. Sorry to say that you'll need a specific service manual for that specific engine to do that procedure.... or extremely lucky guess work.
 
Thanks for that. I did a bit more research and found that out too. It looks like its a 1983 or earlier. The freeze plug has the code C0400119 on it.
It does have the threaded rod attached to the vertical throttle arm of the engine that has a nylon clevis attached to the threaded end which controls the metal cam.
I will get some pics in the morning here and post them to see if anyone can guess its date. Apart from adjustments, for an oldie, it runs superb and is very quiet although it cranks for a while before it starts. As soon as I can get a date for it, I will get the proper manual and sort it out.
 
Unfortunately the number on that core plug doesn'r help us. You say and I quote "It is a premix engine and has not had a VRO pump taken off it."

I assume that means that the engine has never had a VRO installed and has always been a premix engine. As such, I agree with you that it could be no later a model than a 1983 115hp model... IF... it is indeed a 115hp model. Does the engine's carburetors have "Choke Butterfly" plates... OR... is the engine equipped with a small black fuel primer solenoid?
 
pic2.jpgPicture 1pic1.jpg
 
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The only V4 models that had a combinaton of choke butterflies, dual powerpacks, and used a electric choke solenoid attached to the top starboard portion of the carburetor face plate, was 1978 and 1979. Your engine would need to be one or the other.

In 1980, the fuel system changed to the fuel primer solenoid setup which replaced the choke butterfly carb setup along with the choke solenoid.

The vertical throttle arm linkages seem to be normal (what I can see of them) leading to the carburetor cam and roller.

The vertical throttle arm is a spring loaded two piece arm... you do know that don't you? After the top portion has the timer base pressed up against the full spark advance stop rubber button, the bottom portion of the vertical arm continues onward towards the rear of the engine which causes the throttle linkage to open the throttle butterflies fully!
 
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I had forgotten about the 2 piece arm. I will check that out. Thank you very much.
I have some other pics but not loaded them yet. This is a 115Hp is it? and not a 85Hp.
While i'm here, I have just been offered a 1990 140Hp with a corroded cylinder where someone has left the head off. If I were to buy it and it does not bore out within available oversize pistons, are sleeves available?
 
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