Johnson 70hp VRO from 1986 dying when going on idling / low rpm

[andy65]

My Johnson 70hp VRO from 1986 is dying when going/drifting on idling / low rpm, and I don't think that the idle is too low. Do you have any suggestions what can be causing this?

Thank you very much!

 

[jimlansing]

Re: Johnson 70hp VRO from 1986 dying when going on idling / low rpm

I've got the same problem. Check it out:

I have a 1986 Johnson 120hp VRO engine. I just put a new fuel pump on it without the vro pump and am adding oil with the gas. It starts, idles and runs great! until you put it in gear and acclerate. Just putting it in gear is ok, its when you accelerate that it coughs and dies. I can slowly take it up a little then push it wide open and it will eventually open up and run great at high speed until I stop or slow down, then we start the process all over again. It seems to "release" right around 2000 rpm and runs very smoothly. When the engine is in nuetral you can open it all the way up and it runs great. It's only when you accelerate in gear that it coughs and dies. Any ideas? Any and all helpful suggestions will be greatly appreciated.

Let em know if you get any responses and I'll do the same. Thanks! Jim

 

[tashasdaddy]

Re: Johnson 70hp VRO from 1986 dying when going on idling / low rpm

jim, your sounds like a link & sinc problem, the carbs and the elect timing is off, and not working together. both of you the idle speed needs to be 600-700 IN GEAR, IN THE WATER. it will idle higher in neutral, and on muffs, as there is no back pressure on muffs.

 

[andy65]

Re: Johnson 70hp VRO from 1986 dying when going on idling / low rpm

You are of course very welcome to submit to the thread, Jim, but I don't think we have the exact same problem. My engine are more than willing to accelerate and run at high rpm, however, if I've run at idle or very low rpm the engine suddenly dies, and then becomes hard to start, could it be flooded?
How do I adjust the idle speed, is it the black plastic nut with four tips on the left side of the engine (looking from inside the boat) that I should tense?

 

[tashasdaddy]

Re: Johnson 70hp VRO from 1986 dying when going on idling / low rpm

the idle speed screw, have someone move the throttle, watch the engine linkage, when it come back to nuetral the is a long bolt, should have a rubber tip, that stops the movement. this is the one on an 88 88spl, lots the rubber tip. screw it in the faster the idle, out the slower the idle.

 

[andy65]

Re: Johnson 70hp VRO from 1986 dying when going on idling / low rpm

the idle speed screw, have someone move the throttle, watch the engine linkage, when it come back to nuetral the is a long bolt, should have a rubber tip, that stops the movement. this is the one on an 88 88spl, lots the rubber tip. screw it in the faster the idle, out the slower the idle.

Thanks!

On my engine ,there's another screw that looks exactly like the idle speed screw, located a few inches above, which seems to block the engine linkage at the end position - what is it for, and how should I adjust it?