Cooling issue

[edodds]

Ok folks this is a wierd one. My engine is a yamaha 1994 P150TLRS. The last three times I have been out it has overheated and has trouble pumping water when I am at an idle. I have changed the water pump, flushed the entire cooling system-ran acid through it-replaced thermostats, i have checked evrything. When I am on plane I have about 15psi of water pressure, the problem is just at idle or when I am flushing the motor at the house. Another thing I have noticed about this engine. The first time I replced my water pump, I had to reuse the old housing and insert cartridge, because the new ones would not fit over a series of washers and spacers that sit on top of the impeller. I asked the guy at the part store and he said that you did not need them. That all they were for was to keep the drive shaft from chattering at idle, and that the housings and insert catridges were made to fit tighter. So the last time I changed the pump i used the new housing and insert cartridge. And I double checked the part #'s to make sure they gave me the right part. Another note these washers are not listed under water pump repair in any of the manuals, they are in the manual on some diagrams but not anywhere related to water pump. I anyone is familiar with this engine please help.

 

[BRIAN03]

Re: Cooling issue

Check the bypass valve. It sounds like it off its seat or the rubber grommet has been damaged. If it has good water pressure above 1000 rpms check the bypass valve. I would not use an after market Impeller in this engine. When the impeller is replaced make sure the wear plate under the impeller is flat and true. Yamaha parts only.

 

[rodbolt]

Re: Cooling issue

hello<br /> yep what brain says. check the pressure relief vavle. usually a thourough cleaning of the valve pocket with a bent pick and a new grommet will work. I would also change dealers for my parts. they really sold you a monkey. the insert and housing are different from 95 up on the v4-v6 due to the mod to help prevent chatter. the retainer and washer and cup assy that is on top of the impeller are on the micro-fiche. sounds like you have a later gearcase on that motor than the year of the motor. but like I said. change dealers before they create a problem. I hate to see misinformation put out by dealers and parts dudes. if they look in the footnotes in the accessories manual or parts smart it will state that some have to change housings and cups. you really should put the sping washers and spacers back on. all they do is help keep the drive shaft thrust bearing from pounding, I mean chattering, against the drive shaft bearing and housing assy. bearings like rolling not pounding

 

[edodds]

Re: Cooling issue

I found out something interesting the other day. After obtaining all the part numbers from yamaha's web-site, I called the local yamaha dealer to see if they have them in stock. One thing jumped out in particular, the insert cartridge(water pump)had one part # if you bought it by itself and a different part number when it came in the kit, I dod not know if this is just a numbering issue or if they are indeed different cups.