engine over heating

E

edthearcher

New Member
Nov 11, 2013
22
madison wisconsin
Boat Info
1986 22 foot pachanga
Engines
magnum 350
need some direction please. last fall i tried to pump into my block some 60 degree burst rv fluid, screwed up and never drained the block first, my mistake. so at the suggestions on here I drained the block, took off the thermostat housing poured 100 degree below zero burst RV fluid onto the block also all 6 hoses going to the thermostat total of 5 gallons. so a couple of weeks ago I went to the local mercury marine parts dealer they sold me a 143 degree thermostat and, gaskets plus the brass sleave that sets ontop of the thermostat installed and hooked up all the hoses. hooked up the ear muffs to the lower unit, turned on the engine, the thermostat guage got up to around 200, so turned off the engine, drained all the R.V. fluid from the block, towed the boat down to the lake put it into the water started the engine and once again it started to over heat, opened up the drain plug on one side of the engine and got clear water, so now that tells me my lower unit impeller is working. I was woundering if it could be the engine water water pump orr what to check for. I have a 1986 sea ray pachanga with a rebuilt 5.7 350 magnum engine. any help would be greatly appricated thanks in advance ED:smt021
 
I'm assuming you were winterizing your raw water cooled engine. Do you have a water pressure gauge? I would suspect that even though you're getting some water flow, your impeller is ready for changing. When the engine runs, is there any water escaping or squirting out between the drive and the earmuffs? When I start my engine the water goes from squirting out the sides to being sucked into the drive with nary a drop spilled.
 
Alpha drive? That won't suck as much water in as a Bravo. Also depends on how much flow your hose is putting out. But since it did it at the lake, it "could" be the impeller. If you don't know when that was last changed, or it's been at least a few years, it's a good idea to change it.

Did you make sure the t-stat is in properly?

Before you do any of that stuff, though, since you said you have (6) hoses at the t-stat housing, then it sounds like you have that spring-n-ball set up in the top two hoses (the "T" section). Remove hoses, remove spring-n-ball set-up, manually stretch the spring making it an inch or so longer, reattach and see what happens.
 
sounds like good advice, yes I have the spring loaded T. I was going to order a complete housing but its $345, so not to sound stupid just what does that spring loaded T do, can I just pull out on one side than the other, or do I have to remove the balls.I think there was a small nut at the end of each one. when i put her to bed last fall ran like a dream, the other thing I was wondering if the water pump in the lower front of the engine also could be weak?
 
The recirculating pump on the front of the motor rarely gets weak. They usually work or they don't. Usually if the motor gets warm at idle it is the water pump in the outdrive. As Dennis said, if you don't know when it was last done pull the lower unit and make the repair. If you have not done this before but feel capable, look on YouTube for a video of the steps. It's really pretty easy.
 
thanks for all your advice I just remembered something, I down loaded the directions on the thermostat . there is suppose to be a gasket between the top of the thermostat and the thin brass sleave that goes on top. when i took it apart there was no gasket there. when i put it back togeather i installed the gasket, but it pushed the brass sleave above the face of the thermostat surface, this would not allow me to put the top cap down tight even with the top gasket in place. to i carefully had to remove the sleave take the gasket out than the 2 surfaces matched great.
 
correct me if I'm wrong but when you have your boat on a hose muff unless the lower unit water pump is blocking the flow of water isn't the hose pressure and flow high enough to supple the motor with water no matter what condition the raw water pump is in?
 
dvx216 said:
correct me if I'm wrong but when you have your boat on a hose muff unless the lower unit water pump is blocking the flow of water isn't the hose pressure and flow high enough to supple the motor with water no matter what condition the raw water pump is in?
Click to expand...

If the impeller is mostly intact, it can block the flow. I just did my Alpha water pump replacement 2 days ago, and the flow can absolutely be blocked, no matter how hard you turn on the hose (which I learned about 30 minutes before tearing open my outdrive). My old impeller was actually in one piece, and looked to be in decent condition. But it wasn't pumping water at all, while the replacement is working like a charm.
 
well guys I would like to take a sec. to thank all who replied to my posting, just got the boat back, the lower unit impeller was not only worn it was fried, also the housing was bad. he replaced it, toped off all fluids, changed oil, total came to $225. I was a happy camper, thanks again ED
 
At least from me....de nada. It doesn't take long for that impeller to take a set and stop functioning. This is a pretty easy fix and something that you may have to do every year as part of your re-commissioning.
 
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