130 tlrt.water pump impeller

[nicefishman00]

i removed and replaced water pump impeller,started eng. on the hose and water press and flow was normal, advanced to 2200rpm water pressure dropped to below 10psi..stopped moter,restarted pressure and flow normal again advanced throttle again flow and press drops below 10.whats up???

[boats.net]

V4 and V6 engines need more water than you can get on a water hose flusher. You might water test and see if holds pressure.

[Ken]

brian,
Don't 'ya just love it when you try to fix something, and then something else goes wrong !! Been there - done that!!
I'm gonna guess you either have something wrong with the pressure gauge, or the pressure control valve (poppit) is pre-maturely opening.
Check all tubing connections from the motor to the pressure gauge for any leaks. Maybe when the pressure builds up, a leak in the tubing is occuring and the reading on the gauge drops. Or there is something wrong with the gauge itself.
The pcv is designed to open at approx 20 psi to relieve over-pressure in the water cooling system. A faulty pcv can open pre-maturely and dump water and the pressure will go down. The cooling water will dump out the relief holes at the top of the upper casing when this happens. Check those holes for this when your symptom occurs.
Good luck, and let us know what you find,
Ken K [img]smile.gif[/img]

[tripleb]

Hey nicefishman00,

Ken has given you some excellent advice ..... I would also suggest that you may not have enough water pressure from the garden hose.

[Ken]

brian,
I agree with boats.net and tripleb that you need to put the boat in the water to do your pressure test. Could be that the new impeller is sucking air at the higher rpm.
Good luck [img]smile.gif[/img] ,
Ken K

[brougham]

Hey guys,

I'm new to the forum, and just recentlly purchased a 92 Maverick with a 92 130 yamaha. I've been dealing with the issue of overheat alarm at high rpm's (4000+) also. I've been trying to do the repairs myself with some success, lots of fun. I've purchused PCV, spring, and gasket. I need your help with how to install. Pictures would be awesome. Thanks

[99yam40]

You have added to an old thread. you need to start your own thread by clicking on the Create new thread button on the top of the page.

Buy yourself a Yamaha service manual for the motor you have, you will need it and it will save you many hours instead of looking for it online and asking for copy righted material out of manuals that most people will not send.

I have read that the PRV will cause low RPM over heating when not closed properly but not high RPM problems. That would likely be thermostats, water pump, or some blockage for the most easy fixes