97 Yamaha ProV 115 Dies at WOT

[Chad36526]

I have a 97 Yamaha ProV 115 on a 17ft. Bullet Bass Boat that dies out after a mile or two when running WOT. I have changed plugs and have good spark on all 4 cyl. No alarms sound when engine dies totaly off to dead stop, I can restart imediatly and run for a mile or so more. Any Ideas?<br /><br />What should the Water pressure be running WOT on this motor? I'm currently between 7-9 psi with a good strong stream comming out the discharge.

 

[terryc]

Re: 97 Yamaha ProV 115 Dies at WOT

This is a long shot, and may be of no help. Could it be that the safety cut off connector on the forward controls is causing motor to cut out. i had this in a suzuki 140 some years ago, a simple thing that is often overlooked. It may be not holding on firm enough when you are pounding in the water.

 

[Chad36526]

Re: 97 Yamaha ProV 115 Dies at WOT

Thank you for the reply, I will check that this evening! This only seems to happen if I am above 5000 RPM, If I stay below 5000 it never stops. Maybe the carbs are not adjusted properly? I tried both 1.5 and 2 turns out on the high end adjustments with the same results.

 

[rbu]

Re: 97 Yamaha ProV 115 Dies at WOT

Chad,<br /><br />I might be wrong about the newer Yamahas, but the late 80's ones did not have high speed carb adjustments. The mid and high speed jets were all fixed jets. I would think that much hasn't changed on carb Yams, that might be why you have not seen any change when adjusting the screws, you were adjusting the idle air mixture. Just a thought ...<br /><br />I would look into what Terryc says, about the kill switch, look over anything that is simple, wiring connections fuel connections etc ... My initial guess would be electrical since you said that it just stops dead.

 

[Pro Crappie Guide]

Re: 97 Yamaha ProV 115 Dies at WOT

What did you come up with on this? Anything?<br /><br />My 96' Johnson does the same thing, kills at accelerated throttle, just like I hit the switch, but immediatly restarts.

 

[Down South]

Re: 97 Yamaha ProV 115 Dies at WOT

It may be a restriction in your fuel system. Check the fuel filter, hoses for kinks and for obstructions in the suction hose in the fuel tank.<br />Fuel pump may be crapping out too.<br />You might want to try keeping pressure on the bulb while at WOT to see if this will keep it running. If so, it's the fuel pump or sucking air.<br /><br />Good Luck

 

[Chad36526]

Re: 97 Yamaha ProV 115 Dies at WOT

My kill switch wirring looks good so far. I couldn't take the boat out yesterday as planned but will definately be out this evening tinkering with it. <br /><br />Anybody have numbers on waterpressure for this motor at WOT.

 

[Chad36526]

Re: 97 Yamaha ProV 115 Dies at WOT

Definatly not the kill switch, i foud that when it dies out at WOT I can back off and feather the throttle and the motor comes back. I checked the fuel bulb and it was firm. What do you think about a bad fuel/water seperator?

 

[rbu]

Re: 97 Yamaha ProV 115 Dies at WOT

Whenever I try to diagnose a fuel related problem, I like to start by running the engine off a 6 gallon tank. If the problem persists on the portable tank, then you're problem is with the engine and you can move on to checking the fuel filter on the engine, the fuel pumps and the carbs. If the problem does not show up with the portable tank, then look into your fuel lines, primer bulb, water seperator, fuel tank pickup.<br /><br />I noticed you said that you don't have the problem if you stay below 5000 rpms. After checking with the 6 gallon tank, you might want to check the adjustment on your floats. Maybe your float bowls can't keep up with the fuel demand over 5000.

 

[Chad36526]

Re: 97 Yamaha ProV 115 Dies at WOT

I replaced the Fuel/water seperator last night and found that the old one was full of crap. I also cleaned the fuel filter before the carbs and it seemed very clean for the condition of the seperator. I also found a very small fuel line leak comming into this second filter that would show if you held pressure on the bulb for 30-40 seconds. I'm going out again the evening to test. If this does not work I will begin with the 6 gal. tank to diagnose. Thank you for the help RBU! I will let yall know the out come on Monday. <br /><br />Any idea on waterpressure at WOT for this motor?

 

[Chad36526]

Re: 97 Yamaha ProV 115 Dies at WOT

Looks like the Fuel/Water seperator and very small gas line leak was it. Thanks for the assistance.