96 130 hp idling issue

[lacsamana]

Hello everyone, I am new to this forum. Any advice would help. Last season my VRO pump seem to be mixing too much oil with the gas to the point were raw oil was in my fuel line. I decide to plug the oil port and mixed my gas 50:1 the old school way per OEM manual. Now my engine seems to be fluctuating when at idle. RPM 1100 to 800 every once in awhile but very noticeable. High to low. As the engine gets warm the idling issue is not a frequent but still there. Has anyone had this issue before. Could it be something with the VRO pump. Any input would help. Thanks, Norman

 

[Chris1956]

Re: 96 130 hp idling issue

Idle fluctuation can be caused by air leaks around the carbs.

BTW- a symptom of over oiling by the OMS pump is caused by air leaks in the gasoline side of the fuel system. Perhaps your OMS pump is still good?

 

[clemsonfor]

Re: 96 130 hp idling issue

i would just pull all the carbs and clean them, that age motor prolly will benefit from it if not done already. This will also gaureentee that there are no leaks and all lincages are sinked up right and opening.

 

[lacsamana]

Re: 96 130 hp idling issue

Thanks guys for the quick reply....that really helps. I'm going to take the carb apart and clean it....do you think the vro oil pump is worth reconnecting?

 

[Chris1956]

Re: 96 130 hp idling issue

You can reconnect the oil line to the OMS Pump, and purge it of air. Fill the oil tank to the top and run 12 gal of premix thru the motor. Now see if the oil tank will take about 1 qt of oil to refill it. If so, it is likely operating properly.

 

[lacsamana]

Re: 96 130 hp idling issue

Ok....thanks Chris. I'll try thanks. Sorry about all the questions. This may sound stupid but, if it was an airleak on the gas side, wouldn't my motor be starving for fuel when I throttle it. The fluctuations only happens at idle. I also read in my manual about sychronizing throttle valves.

 

[Dhadley]

Re: 96 130 hp idling issue

That motor should idle at about 800-850 in neutral, in the water when warm. When it first starts up cold it'll be in Quick Start and may well idle at 1100 until it warms up. Out of the water it may idle at 1100 even when warm (no backpressure). This is assuming the t-stats are in and operating correctly, you have the right spark plugs and the motor is operating otherwise as it should.

 

[lacsamana]

Re: 96 130 hp idling issue

Thanks for the info DHadley.....

 

[Chris1956]

Re: 96 130 hp idling issue

The air leaks into the gasoline side are what cause the over oiling. The airleaks can be small enough where they do not affect engine operation, outside of the over oiling.

Any airleaks into the motor (around the carbs, crankcase cover etc), will cause fluctuation in engine speed.

 

[lacsamana]

Re: 96 130 hp idling issue

the fluctuation only happens on idle.....the over oiling issue makes sense. What do I need to do.... alot responses say do a vacuum test on the fuel line. What would you do first?

 

[Chris1956]

Re: 96 130 hp idling issue

I would first inspect all the fuel line connections, water seperator or fuel filter, connections to primer and motor as well as tank. Look for anything that may leak air. Also inspect the main strainer under the airbox.

Next make sure carb bolts are snug. Perhaps one of the spagetti seals under the carb is broke, and leaking air into the manifold. You can spray some 50::1 mix around the carb and see if the motor speeds up or slows down. That will be the source of the air leak.

 

[lacsamana]

Re: 96 130 hp idling issue

Ok Chris...many thanks for the advice. I will definetly try that. I'll update on a post

 

[lacsamana]

Re: 96 130 hp idling issue

I did find the mechanic that plugged the oil intake side of the vro pump was dry rotted. It broke of easily when I moved it. I haven't tried to start it because I haven't had a chance....I'll do it tomorrow. Do you think air getting sucked in by oil intake can cause the idle hesitation?