Pulse hose on johnson 50 vro

BOWMAKER1

Seaman Apprentice
Joined
Jun 9, 2011
Messages
46
We are getting a good start on the rebuild of my old boat and have a couple more questions. Motor is a 1985 Johnson 50 J50TLCOB with VRO. There is a hose that basically fell apart as we were trying to get the shift bolt out to remove the lower unit to replace water pump. The manual calls it a pulse hose and it has a filter or a spark arrestor in it and needs to be serviced as a unit. What does this hose do and what does it connect to? Can I just replace it with a piece of fuel line hose? I intend to disconnect the VRO and just run premix gas if that makes any difference on this issue.

Next question, there seems to be some clear rubber hose that is on part of the throttle linkage. A parts breakdown from ishopmarine calls it a roller sleeve and it looks like there is one for each carb, but it says obsolete. Are these something special, and are they necessary, and can I still get them because they have fallen apart also. This motor has been sitting on the boat out side for 7 or 8 years with out starting. Motor does turn over and appears to have plenty of compression from just rolling it over with a plug out but haven't put a gauge on it yet. I wanted to get the new water pump in first and then these hoses started falling apart, so we haven't even thought about trying to start it yet.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Pulse hose on johnson 50 vro

The pulse hose is a pressure-vacuum hose from the crankcase to the VRO. The pressure-vaccum pulses from the engine are what operate the pump. There is a pulse "limiter" in that hose. The limiter is screwed into the crankcase and a hose connects it to the VRO. Standard fuel line hose can be used. Without the clear tube on the rollers it may be difficult to get the proper link&sync settings on the carbs. Try a couple layers of clear heat shrink tubing.
 
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