Need some advice
 

I have a 1997 35 Lighting with 500HP's.
The starboard engine over heats. It cools off at idle but when ever running over 3000RPM is creeps up and eventually over heats.The actions I have taken have been
1. New Impellers
2. Reverse flushed engine
3. New Water circ pump
4. New thermostat

what next? it is still over heating, I noticed that the water pressure guage shows low pressre. Does anyone know where this guage is in the system???

Thanks and best regards to all

Re: Need some advice
 

Did you post in the tech section? You will get more replies there.

Re: Need some advice
 

Have you ever fried an impeller on that engine? Sometimes the pieces can clog up the cooling system and cause overheating long after you have put in a new impeller.

Re: Need some advice
 

StarLoone

Water pressure is taken off the block. What is your pressure when crusing 3000 rpm? Does it go up when you go faster?

Re: Need some advice
 

I am reading about 4 (PSI I assume) on the guage and around 8 to 10 on the Port (which is running between 130 and 148 degrees...

Re: Need some advice
 

You should have 18 - 20 lbs of water pressure at wide open throttle. What kind of water pick-ups do you have? Are they the stock Bravo side pick-ups or is there a factory nose cone with a water pick-up on the torpedo? When you are in neutral and raise the engine rpm what kind of pressure do you get at 3000 rpm?
Dan

Re: Need some advice
 

I was told that Merc. only needs about 3 lbs of pressure to cool properly. My guages read 7 on port at 3800 and 12 on Star. The drives have the low water pic-ups.

Re: Need some advice
 

Oh and i am reading 150 degrees at full on both sides

Re: Need some advice
 

Hey Fountainfamily what are you doin saturday Im headin out to the delta so just seein if you might be takin that new Fountain out.

Re: Need some advice
 

I had the same problem a few years ago. Check the threaded inserts that hold the short hose going from the outdrive bellhousing (what the drive bolts to) into the boat. There are two bolts to remove the housing inside the boat to check this insert. The insert inside the boat had collapsed on my boat and was restricting flow. I eventually found it by backing the boat in the water enough for the drives to pick up water, started both engines, throttled it up and witnessed reduced water flow out of my port engine above 3000 rpm. If this is it, it is a relatively easy fix, although you will need a special tool to install the new inserts. I got mine at a local Mercruiser dealer.

Re: Need some advice
 

You are misinformed. That is not enough pressure to give a complete fill, possibly allowing for air pockets in the heads, and possibly a higher false temp reading because the sender may be registering a steam pocket, not water temp.
Stock HP500's will have around 15-20 at WOT. Since you stated new circulating pump and t-stat, that eliminates a crossover setup which will give low pressure.

Something is blocked/not right. Double check the inlet supply hose from the transom to the sea water pump for blockage or a kink. That hose HAS to be hardwall. You can't squeeze it by hand. Also remove the hose on the outlet side from the seawater pump, then remove the hose end right before going into the t-stat housing and back flush that line making sure no broken impellor parts come out a tthe seawater hose end.
You did install the hoses on the right ports when you replaced the impellor? That will give the symptons you are seeing too. If all checks ok, check the flow from the drive pickup to the seawater pump.

Good Luck

Re: Need some advice
 

Thanks for the info. I will look into the hose routing and see if there is any blockage anywhere. t we will be on the lake this weekend on sunday.

Re: Need some advice
 

Hey Fam. Dont you live at Disco. Bay, so what lake are you goin to. I want a ride on your boat Ha Ha but seriousley lets meet up sometime. My name is Chad call me if you want man
916-837-1379 we'll have a cocktail.

Re: Need some advice
 

We are headin up to Berryesa on Sunday. We have a 4 year old and it will be her first trip out. We live in Green Valley.