1990 150HP VRO

[vtrufus]

I am having a what I think is a fuel advance problem on my engine. Here are the symptoms... It starts fine and idles great, when I give it power under load to say pull up a skier, it hesitates and sometimes dies. I took apart all 3 carbs and none have any obstructions, and since its fixed jet there are no adjustments. I then checked all 6 coil packs and I have blue sparks on all of them. All of the plugs look ok too. Changed my fuel bulb to see if I am losing pressure and that did not help. The fuel bulb does not stay completely tight all the time, but it only takes on pump to get it back tight. I checked for air leaks in the line and cant find any. I have an electric choke, and when I hit the button it helps to some extent, but not the cure. It also does not top out like it used to. It stays at 4200 rpm where it used to top around 5200. I noticed the small air pickup hose which connects from the air box on the front of carbs to the head has a big cut on it. What does this line do, and could this solve my problem. Also where does the engine get its load reading for fuel advance??? Is there a vac sensor somewhere that is going out??? Any help is appreciated. I do not want to drop a load at the dealer on a witch hunt.

 

[ob]

Re: 1990 150HP VRO

The only thing I can think of is to check the carb linkage roller and insure that it is on center and just touching the fiber throttle cam when the controls are in neutral.Past that it seems that the limited rpm symptom tends to lead one back to the carburetors.<br /><br />When you serviced the carbs, did you also insure that all of the carburetor bowl pickup tubes were clear and unobstructed?Also insure fuel tank is venting properly and tank fitting anti syphon valve is not defective ,causing restriction.Last but not least,with the intake cover removed ,make sure all carb flaps are opening equally to full horizontal when controls are at WOT and back to full closed when returned to nuetral.

 

[seahorse5]

Re: 1990 150HP VRO

Did you remove and clean the mid-range jets from down inside the float bowls? These are not the high speed jets from the bottom of the bowls.<br />If not, there is your hesitation. Make sure the floats are set just above horizontal and that the float drop setting is correct. Did you use the factory carb repair kit with the brown colored alcohol resistant gaskets in it?

 

[vtrufus]

Re: 1990 150HP VRO

Yes, I have the brown colored gaskets on the top of the float bowl. I appears that the butterflies are horizontal at WOT also... I may have to pull the carbs apart and see if there are any more obstructions in the jets. Does anyone know what the vacuum hose does I mentioned??

 

[ob]

Re: 1990 150HP VRO

Sure .The crankcase scavenges from the silencer preventing excess accumulation of residual fuel mix.

 

[vtrufus]

Re: 1990 150HP VRO

Thanks, that makes sense, similar to the air recycle system on a car. Do you think a big hole in that hose would cause my problem?

 

[ob]

Re: 1990 150HP VRO

I don't think so.However ,a leak in the VRO pulse hose would.