How do you test Yamaha V6 recirculation valves?

[iammarcuse]

I have a 1991 ProV 150 Yamaha that has a chronic lean sneeze and often times stalls at idle. It runs fine off idle and makes 5500 RPM at WOT. I have removed and cleaned carbs twice. They are spotless and every jet and passageway is clear as checked with compressed air. It has new spark plugs, lift pumps and filter. The ignition side seems good and wires and caps ohm out properly as well as spark tester confirms consistent spark. Compression is good. There is no anti-siphon valve or water in fuel.

The only possibility I see left is the recirculation valves. I have tried testing them with a squirt bottle. It seems I can push air in AND out. All six are the same. I doubt I have 6 bad valves. Do I need to use liquid (alcohol) in order to get the check valves to close when I suck back? If I pull the hoses while idling I can feel air pulsating in and out. I also figured if I pulled the right one then the sneeze would quit while I had that hose off. No such luck... for one thing the sneeze is intermittent and doesn't always happen. I also fattened up the starboard side pilot screws from 3/4 turn to 1 turn. That has seemed to help a bit. I am scratching my head here. Any thoughts? Frustrating.

 

[erniefish]

Re: How do you test Yamaha V6 recirculation valves?

FYI, I HAVE A 150 TXRC(2004), i had four bad re/circ valves, they are check valves, and only go one way,take a small syringe with small rubber hose ,fill syringe with alcohol and attach to nipple on valve, squeeze about a third of syringe, then attempt to pull back, syringe should "lock up", i do not know why i had four bad ones, but i did, they are cheap to replace, let us know if it worked

 

[iammarcuse]

Re: How do you test Yamaha V6 recirculation valves?

Thanks Ernie
I saw your other post on this and that is why I was looking into it. Did the new valves solve your idle problems?

 

[erniefish]

Re: How do you test Yamaha V6 recirculation valves?

yes it did fix the problem, if i had a dollar for every time i took those carbs off, i even had a proffesional (friend) clean them ,to no avail, i had never had a problem with re-circ so it did not enter into my equation,but you can bet it does now,my only guess is a bad run in production, is why four failed on my motor, i would replace all of them, they are cheap, a little bit of a pain to do, but worth it!, let me know if it works

 

[iammarcuse]

Re: How do you test Yamaha V6 recirculation valves?

According to boats.net my motor has check valves on both the intake and crankcase side. http://www.boats.net/parts/search/Yamaha/Outboard/1991/P150TLRP/parts.html They are different part numbers but both listed as check valves. I am a little perplexed as I do not want to change nipples... only the check valves. The crank side is definitely blowing back towards the intake but maybe the check valves are on the intake side. Do you think it is possible for there to be check valves on both ends?

 

[iammarcuse]

Re: How do you test Yamaha V6 recirculation valves?

Ernie
Did you just test and change the ones on the crankcase side? How do you put the new ones in? Do they need to be tapped in with a mallet or small hammer what?

 

[iammarcuse]

Re: How do you test Yamaha V6 recirculation valves?

Five of the six valves on the crankcase are shot. I might as well do them all. I still am not sure how they go back in. ???

 

[erniefish]

Re: How do you test Yamaha V6 recirculation valves?

yes, the ones on the side of the block, ( not the nipples on the front of the motor), grabbed them with vice/grips, some came out easy, some were a ***** and yes tapped them in with a aluminum dowel rod,

 

[CharlieN]

Re: How do you test Yamaha V6 recirculation valves?

Good info in here, on my new to me '86 ProV 150 I find one bad valve, bottom port side. The others test fine. I used Jameson to try and get the taste out of my mouth from testing them.
I pulled two valves out, the good one has a small rubber element in a brass holder, the bad one was a clear shot through so spraying a solvent in will not free up a sticking valve.
Thank you again for leading me in the right direction, I am ordering a few valves now.