ProV 150 Surging at WOT where to start?

[RangerJer]

92 Yamaha ProV 150<br /><br />It starts and idles great. Also does not seem to do at under 4000 RPM<br /><br />Anything over 4000 RPM and at WOT the motor surges and kind of hesitates, loosing rpm slightly. I am looking at the fuel bulb or the fuel pumps first. Is this a good start? The bulb seems to hold good pressure. Im not sure how old the pumps are so I am thinking of just replacing them. Let me know what you guys think.<br /><br />For the pumps is it easier to just replace them or is it ok to rebuild? Any idea on costs of each route??<br /><br />Thanks in advance for some ideas on where to start to fix this.

 

[bryan c]

Re: ProV 150 Surging at WOT where to start?

i have 1990 150hp.does same at 3500 and wot. im also looking for ideas.

 

[Ray Neudecker]

Re: ProV 150 Surging at WOT where to start?

I have had much better luck replacing than rebuilding. The symptoms are of a fuel restriction and that is an excellent place to start.

 

[RangerJer]

Re: ProV 150 Surging at WOT where to start?

Hi all,<br />1992 yamaha ProV150<br /><br />Replaced both fuel pumps. Checked filter and all lines. Engine still hesitates and loses punch at WOT. Starts and idles good.<br /><br />Could this be a plug issue? They seem to look fairly good. Also check Pump Bulb. IT seems to hold the pressure just fine.<br /><br />Where else do I look next. Is this a carb issue, Have used stabil for longterm storage and use seafoam in every tank while motor is in use.<br /><br />Thanks

 

[bossee]

Re: ProV 150 Surging at WOT where to start?

Hi,<br />Do You have a fuel/water separator?<br />If no - consider one.<br />If yes - maybe change the separator element?<br /><br />Also make sure You are using the recommended spark plugs and correct gap. If You have not changed the spark plugs in a long time it maybe is time for new (regardless if this problem).<br /><br />At least some more items on "suspected" list to check...

 

[RangerJer]

Re: ProV 150 Surging at WOT where to start?

Hi all<br /><br />Rodbolt and all......do you have any ideas whatelse I should check for with a slight surge/hesitation at WOT??<br /><br />RPMs will drop a littel once at WOT,,, speed will go down. Motor starts and Idles good.<br /><br />See above for what I have already done...both fuel pumps are new.. check filter, is clean.. checked fuel lines, all look good. Motor is in great shape. I do put seafoam in as well.<br /><br />Plugs are fairly new however, could it be the plugs? I was looking into having the carbs redone and cleaned.... <br /><br />Any ideas are appreciated...<br /><br />Thanks<br />Motor is again a Yamaha ProV 150 1992

 

[Ray Neudecker]

Re: ProV 150 Surging at WOT where to start?

Redoing the carbs is the most logical thing now. Most surges in a Yamaha are caused by some fuel restriction.