1993 pro-v 200 model p200TLRR overheating

[bassinflats]

Two years ago started having a problem with motor overheating when I went above 4300rpm. Got boat in 1997 and was always able to run at wot. When problem first started replace water pump which I do every year, then tried thermostats, still no help so took it do a dealer. They took the water jackets off and bead blasted and cleaned, cost me $600 lasted about four months and problem came back. Took to another mechanic and they suggested pulling power head and checking water jackets in foot, they cleaned and show me debris looked like grass and sawdust. After that ran good for another 4 mos and now I have same problem. Checked the thermoswitches yesterday and they are good. Can run all day at 4300rpm but when we go above that to 4500rpm for about 4 minutes will get overheat buzzer, light and throttle cut back automatically, mechanic suggested pulling and cleaning water jackets again. Just can't believe that this needs to be done again only one year later, last time they charged me $900 when the power head was removed. When it does overheat still have good water flow from tale tale no steam and after a few minutes can take right back off as long as it is 4300rpm or lower. Looking for some suggestions of what to try next. Oh yeah have replace prv with new style also.
I have run fresh water for the past 5 years, what to do now.

[Ray Ritchotte]

I'm having the same problem if you read the post 150 pro V overheating.
This is what I have done so far and still no fix.
I pulled the pressure control valve and it was clean with no dirt or debris. Re-installed valve and removed both thermostats and installed new ones. Completely replaced all impeller parts (gasket ,plate ,housing, impeller and checked up inside the lower unit housing. Went to the lake yesterday and the motor is doing the same as yours . I can run at 3600 rpm's all day but as soon as I kick it up to 4300 the alarm,temp indicater and idle protecter all come on after a short while.
I wish that some one would be able to help us out seeing we boyh have the same identical problem. I have not pulled the heads yet and I never run in shallow water. Our lakes in Arizona are 1200 feet deep and canyon walls.

[Tucker]

Cheez looks like you guys have tried everthing. I have the 150 OX66, very similar engine. I know you've paid to clean the water jackets but maybe there was some place you missed. I think I read here about guys that flush their motors with vinegar. If not here over at the Grady forums. There has got to be something blocking water flow somewhere. The flush is for salt water; those lakes in Arizona are freshwater right?

[Ray Ritchotte]

Yes they are and very clean. I am ordering the water prssure control valve to see if that helps. This is very wierd because this motor has given me great service. When I leave the lake I lower the motor up and down to get all the water from it. I store the boat in my garage with the motor all the way down. I have been doing this for years then all of a sudden this overheat thing started. I am very anal about my boat /motor I do all the services yearly in January of each year and I keep a journal on every thing/trip I make with it.
The motor is a 1991 and only has 340 hours on it all by me. This is very low hours for the years I have had it. I do more fishing than running.
Like the other fellow I am stumped at whats happening and being retired its starting to get costly for me. I hope some one out there can help us figuer out whats wrong.
Thanks,
Ray

[Ray Ritchotte]

How would you be able to flush with vineger ????

[BQUICK]

Check your fuel filters and pumps. Might be running lean at higher rpm causing cylinder head temp to rise.

[Tucker]

The PRV should have been checked early. But if the water is a clean as you say, that may not be it. But then again if it's original maybe. Bquick has a good point but I've never head of that happening, still worth eliminating though. Keep us posted with developments.
These guys buy vinegar by the gal and set up a drum with the lower unit in it. They fill the drum with about 10-15 gallons and let the motor idle until it begins to get too hot. Haven't done it but everyone who has says it works great.

[Ray Ritchotte]

Some one suggested to ck the heat sensors with an ohm meter. Does anyone have the proper test procedures ??

[bassinflats]

checked my thermoswitchs in pan of hot water and an ohm meter, they are ok. Ran motor on lake today with cowl off and oil level stays up, but noticed by feeling heads with my hand that the left bank is running warmer that right bank. Just wish I had a diagram that showed the water flow thru heads. Am going to try and check thermostats again and see what they temp they open at. does anyone know if these motors have any water restrictors in them other that the prv. If nothing show up with the thermostate guess I pull the left bank water jackets apart and see what I can find.Anybody else got any other suggustions.

[bassinflats]

anyone know what thermostat temp is for pro-v 200 is

[bassinflats]

Ray jsut got thru reading a txt on iboats about motor with same problem and a mechanic said in the last three years he has found a piece of pencil zinc that broke off and wedged in the block. This was on a 1993 225hp motor but it might be something to look into. Will try to research further for us. Thanks for talking on the phone about problem we are having.

[Tucker]

Holy crap, I didn't know the big blocks had pencil zincs! I must have missed it in the shop manual. I've never changed them in my motor. Can someone please elaborate more about what models have them, and where they screw into the block..

[bassinflats]

pencil zinc

Don't know about other motors but I looked under the parts break down for my motor and it shows aniodes, shows for 115 and 200 hp. Go to boats.net and you can pull up the parts break down for your motor , looked like six on my motor. They look like they bolt right to the crank case. Havn't tore down my motor as yet, still have my overheat problem and very frustrated. No one seems to have any ideas. So after having two service dealers work on it guess I will tear into it myself, if you wanted anything done right you have to do it yourself.

[Tucker]

Guys, the pencil zink breakoff souds like a good candidate. I think the only way to check everything is to pull the water jacket covers on the heads and start probing with a coat hanger. After that remove the exhaust cover water jacket cover(where the poppet valve is). If all clear it has to be an obstruction in the intake tube from the water pump. There's also a cooling passage for the voltage regulator; not sue if it's accessable. Please keep us current with developments. We really need some tech guys to chim in.

[Ray Ritchotte]

Overheat

Bassinflats,
What did you come up with?? I got tired of trying to fiquer out this motor and parked the boat. When I get some money together I am going to have the heads pulled and look at the water jackets. I hate replacing parts that don't seem to be fixing the problem.