Thermostats On ProV-150

[Skeeterman]

I own a 1986 Yamaha ProV-150 (got it new 1986) and never have changed the thermostats in it.
In fact this Yamaha has "never" had a bolt or nut turned on it, with the exception of spark plugs and water pumps replacement. I keep it in a heated or air conditioned garage. I fish about thirty days a year, for the past 20 years.

I'm going to order the parts from this Boats.Net and do renew the thermostats.

How easy it it to do?
I have the ProV-150 manual and the tools. Just wanted to know what trouble there may be facing me.

Thanks.

Skeeter

[Dennisg]

HI Sketter, why fix it if it ain't broke. A lot of bolts might be frozen, and they snap without too much torque. be real careful. If you are not having any problems, don't worry about it. As long as you flushed it out every time it was in salt water, you most likely do not have any salt build up, and you don't have any overheat problems, leave it alone, use the money to buy dinner.That's the only thing that I would worry about.
Good luck, Dennis

[jb123]

fresh water use, shouldnt be any issue. change them,youll need a gasket for both, also the prv parts, fuel pumps,rid of the fuel junction at motor and run hose directly to filter,and lower unit fluid if you havent. ive had an '89 pro-v for 14 yrs now, what a beast !

[Skeeterman]

I, just feel it's safer to change out the old thermostats, new gaskets and thermostats covers. Also may replace the temperature sensors at the same time.

I look at things different than most would. I never worry about the positives, only the negatives. Those little minor negatives turn into large costly negatives. This engine gets the royal treatment. Fuel older than a week gets removed and ran in the lawn tractors. After fishing, and while at the dock, I remove the fuel hose connector from the engine , and run the carbs dry. Fuel filter gets changed twice a year, water pumps get replaced every year. New water separator filter each year, also new spark plugs. The engine has always used Yamaha Ring Free in it from day one. All electoral connectors get cleaned and silicone sprayed on all surfaces.

BTW. The ProV-150 doesn't have a scratch on it, or the Sheeter bass boat. Been offered $7.000.00

Thanks for the comments....

[Hamfisted]

While you're in the mood to replace stuff take a look at replacing the pressure control valve with the new style mushroom head PCV valve ( p/n 60H-12416-00-00 ). The new style valve along with a new seat grommet ( p/n 90480-20M05-00 ) will help keep your water pressure up and reduce any clogging and overheat issues.


-Mike

[slim]

actually if you run this motor at least once every 3 or 4 weeks, it would be better not to run it out of gas as it acts as a lubricant to keep internal carb parts lubricated. any longer then a month and yes you should run it dry.

[Skeeterman]

I, respect your knowledge on running the carbs dry of gas, Slim. Although, I may go two/three weeks before I get it in the lake, I feel the engine gets no chance to gum up the carbs. However, I may have done it wrong for the past twenty years, the "slant-eyed fast paddle" sure has been a good one to take so much abuse.

[jb123]

one mistake i learned from my pro-v is to never choke above say 1500 rpms if you have the spring loaded butterflies, as it sheared and sucked them right into the intake..luckily stopping at the reeds.

[Skeeterman]

Received the Yamaha parts today on replacing the thermostats and gaskets.
According to Yamaha repair manual, there's not to be any gasket sealer or such applied on the gaskets or engine flanges.

I notice, there are less than 1/8" of metal on some areas of these thermostats covers. Do you recommend I use some gasket sealer just to be safe?