johnson 70 vro idle problem...

[razz]

I have a 70 vro that will idle for about 2 min. then stall I have had the cdi box changed ,vro pump replaced,plugs,carbs rebuilt, compression checked all were about 120. the check valve in the vac line to the vro pump was replaced , thermostat was replaced, checked for fuel leaks. It idles for about 2 min the #3 starts to get weaker spark , smokes a little more than just quits..Fuel bowls still have fuel in them . you can hit the key and it will fire up again with a touch of the key ,run for about 2 min then die again. It runs ok at wot. If you push the ign. to choke it, it will flood it and die. If you pump the primer ball no difference.
I am assuming it must be electrical. The #3 coil pack was also replaced. Which direction do I go now??????

 

[fireman57]

Re: johnson 70 vro idle problem...

You don't post a model number so we don't know the year. I'm just taking a stab at this since you haven't had a reply yet. First, welcome to iboats. If the #3 coil was replaced by you and thad to be assembled it is possible that the wire is not down in the coil as far as it should be. I have had problems with that. Since you know which cylinder it is remove and swap the coil to #3 with another one and see if the problem follows. If it does then replace/repair the offending ignition coil.

 

[rickdb1boat]

Re: johnson 70 vro idle problem...

I'm curious. You say it won't idle but 2 minutes, but then say it runs fine at wide open throttle. So does that mean you are only having a problem with it at idle? Does it run Ok at all other times and speeds?

 

[razz]

Re: johnson 70 vro idle problem...

It is a 94 It run ok at other speeds. The above was done at a repair facility.. .

 

[DJ]

Re: johnson 70 vro idle problem...

Grounds (electrical) are a huge issue with OMC's.

Check every ground wire you can find. Pay special attention to the battery/engine ground.

 

[Silvertip]

Re: johnson 70 vro idle problem...

I'll bet you are not losing spark. I think the engine is simply loading up at idle which can be caused by a number of things. Idling too slow, idle mixture improperly set, need for link & sync, carbs need rebuilding, bad gas, water in gas, idle timing. Just a few things to get you started.