spacer plate(?) water passage 120hp '91

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
1.)It's the first I noticed this but is this little hole designed to flow back into the leg? The main impeller to engine orifice is to the right and below the small hole.

spacerplatesmall.jpg


2.)Do I just put a bit of RTV gasket sealent around this when it comes to bolting back onto the leg?

Paul
 

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
Re: spacer plate(?) water passage 120hp '91

Can somebody set me straight on this?
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: spacer plate(?) water passage 120hp '91

It looks to me to be a factory drilled relief hole. My initial inclination would be like yous....fill it up with silicone. But on second thought, they must have a reason for putting it there. Without knowing the reasoning behind it, you may be adversely affecting something else. I know that there are several different springs that hold the thermostat in place. Maybe this relief hole has something to so with that. Controlling the amount of pressure in the water passages vs the spring pressure holding the thermostat in place. Remember, when the motor is cold and the thermostat is closed, you have maximum pressure in the water passages. The spring holds the whole thermostat against the block preventing any water flow until it opens. I don't know. I would leave it as is, open.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: spacer plate(?) water passage 120hp '91

Don't fill it! That hole sprays a portion of the pump water onto the exhaust down tube (that rectangular part bolted to the match plate) and cools it. Not a lot, older engines did not have it, but since it is there, let it work.
 

PaulO

Petty Officer 1st Class
Joined
Jan 25, 2010
Messages
225
Re: spacer plate(?) water passage 120hp '91

From a photo taken when it was dis-assembled it appears the hole was hidden by a buildup of salt or the crap that you can see inside the water passage. There was no thermostat insitu when I took possession of the engine. There is now.

I will treat is as a pressure relief.

Thanks,

P
 
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