Expert: Jeff Grigg - 2/5/2008

Question
QUESTION: just got engine-no history. It stars and runs like a new one but--All cylinders always run to hot to hold hand on-but dont trip temp switches which I replaced-no scale build up under head water jackets.Replaced WaterPump  and Replaced thermostats which would not fully open or close when tested-Still to hot -using pyrometer 150-160F range. warm water pours out anywhere it can on lower unit when on hose. installed  a water pressure gauge by Teeing into telltail hose. only get 11psi at 5500rpm, 10 at 4000 , 6psi at 3200rpm and about 3psi at 2000 at Idle it is maybe .5psi and the telltail has a weak steam. removed LU-connected a hose directly to waterTube- with well pressure of 45psi,(engine not running) my pressure gauge shows about 2psi -telltail shows a stream but most water is flowing down the outside of the water tube like 90% and the rest is making a healthy stream out of a hole inside the midsection just about an inch in front of the water tube where the hose is connected. It appears as if the water is going to the top of the tube and most of it is just running out. I see from the BRP IPBs that there is an upper water tube grommet. If this could be the problem-can it be replaced without removing the powerhead? the next thing I plan on doing is removing the hoses from the heads to verify that all the water I see coming down the water tube is not water that actually did go through the heads. any suggestions/info will be greatly appreciated

ANSWER: The 150 to 160 would be at the very top upper limit of the temp range for your motor. You could have a leak from around the water tube, but I don't think that is your problem.
First of all remove the tee from the tell tale, it is not getting an accurate measurement. Put it on top of the cylinder head.
When you replaced the thermostats did you use stainless models? They last a lot longer. Did you check the pressure valves in the same housing as the thermostats? They need to be able to move freely when under pressure.
You could have a problem under the powerhead, either the grommet or leakage in the gasket or corrosion between the exhaust and water inlet. You will need to pull the powerhead to check. If everything is clean and open it should cool properly. While you have the powerhead off you should remove the exhaust covers in the center of the motor as well. Use a non hardening sealer like Permatex Aviation Gasket Maker on the gaskets.
Post back with what you find.
Jeff

---------- FOLLOW-UP ----------

QUESTION: Jeff,
Thanks a lot even if its not what i want to hear-remove PH.

I don't remember seeing any predrilled/threaded holes in the head water jackets. would teeing in on one of the hoses going to the thermostat manifold be just as good. i have read that the actual number is not so important as long as you remember what you get on that particular engine when everything is cooling properly. That is if mine was running at 125F and I measured 10psi.- i would know to start looking for a problem if I only saw 5psi at the same rpm.but i do like the idea of taking a more real test point.

The pressure valves / seats and springs were good. the old thermostats were not corroded- just not working-I didn't know ss thermostats were available.

If I pull the hoses to the thermostat manifold and block the end of the hoses while the water hose is connected directly into the water tube, should water come out of the midsection? If it still pours out would that be proof that there is a major leak under the power head or is there some other path the water normally takes that will let water come out there? The way I thought it worked was that any water exiting the midsection had to come from the head covers-Is that correct.

Answer
You want as good a pressure reading as possible. Most of the X-flows had a small 1/8" pipe plug in the top of the cylinder head. See if yours doesn't.
If the thermostats are now goo and the pressure valves working properly then and the water jackets on the cylinder heads are clean then you either have a problem under the powerhead or exhaust cover. You could have a small exhaust leak into the water jacket heating the cooling water.
Do all your tests with either the engine in the water, not a barrel, or with the flushing cups. Using the hose directly on the inlet water tube will mask problems and is only good for flushing a motor that has a lot of mud in it. Your water pressure is too high to tell anything.
At this point pull the exhaust covers, and if necessary the powerhead to examine the adapter plate.
Jeff