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1978 V4 85Hp Johnson idles then dies when engine is partially tilted

L

Louie1

Member
Hi everyone this is my first post on this forum. Ive searched through other threads a few times without finding an answer. I bought a 16ft runabout and this motor came with it, it ran fine the first two outings except for being easy to flood and not wanting to idle for long when tilted to the point where the water intakes were just under water. After it conks out and I drop it back down it takes some cranking to get it running again. I checked the fuel line and it appears free of kinks or restrictions and the fuel pump pumps steadily when I removed the hose and checked its flow. I've put carb kits through both carbs and serviced the water pump while at it. The boat has not been back in the water since the carb kits but it runs and idles fine on muffs and revs fine in gear but I still have the same issue of it dying when tilted to about halfway between down and fully up.

The float setting for drop I got from my workshop manual and they were both 26mm which is about halfway between the specified limits. The float when carb body was upside down I had level with the float bowl edge. I adjusted this by slightly bending the arm between the float and hinge pin without loading the needle. I have seen float settings on this forum but they are not in a measurement I can understand.
Do these motors run on half tilt?
If they do what have I done wrong?
Thanks any help is greatly appreciated.
 
They don't run for long at half tilt. The carb needs to be generally level to operate correctly.

Why are you trying to run at half tilt? Shallow launch area or?
 
Hi thanks for the responses. Yes we have two shallow ramps and it’s nice to know the motor is running before we push off into deeper water. It also helps when motoring on and off the beach. All these can be worked around but if it could be improved with adjustment I would go to the trouble.
 
Welcome, Louie. The problem with half tilt is also challenging the water pump. Float type carbs are not effective when tilted past 30 degrees from level either. You should avoid your operating proceedure as mentioned....if at all possible. The water pump is not self priming and needs to be fully submerged in order to catch its prime.
 
Yes, because the prop is spinning, introducing air to the water, so it's not a good situation. It's much different than when up on "step" and you have a constant, uninterrupted water flow below the anti-cavitation plate, where the pump is now lifting the water at a much higher speed with no air pockets.
 
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Pertaining to any outboard running at a dead idle when tilted... the fuel is being forced to travel uphill. Eventually the engine surrenders to gravity.

I once observed the owner of a dealership running a V4 on a flushette with the engine at roughly a 10 degree angle... he, obviously puzzled about the rough running. I caught his eye and motioned with my arm, moving it from an angle to a level condition. He did so... the rough running ceased.
 
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