dt65 over heating

[rolandfrank]

I am going to change the water pump impeller.. anything unusual to look out for when dropping the lower unit?

 

[mphelle8vld]

Re: dt65 over heating

Nothing unusual if you are following a manual, just make sure the linkage to the shift rod is fully dissengaged before lowering the unit.

 

[rolandfrank]

Re: dt65 over heating

thanks .. no manual but I have changed them in mercury and evinrudes. just hope there are no "tricks" I need to know.

 

[rolandfrank]

Re: dt65 over heating

ok.. tried to drop lower unit but I can not see where to unhook the shift linkage.

I figured it would be in the foot..

 

[mphelle8vld]

Re: dt65 over heating

The linkage is under the bottom carb. Loosen the nut on the shaft, slide the shaft over and the pin slides out of the hole in the end of the shift rod.

 

[rolandfrank]

Re: dt65 over heating

yeah I found it.. dropped the lower unit, water impeller looks like new, but put the new one in anyway.. not the problem.. pulled off thermostat housing and there is no thermostat in there. must have been removed already.

it only seemed to over heat under high speed load.. leaky head gasket?

 

[mphelle8vld]

Re: dt65 over heating

You haven't given any info about the history or condition of your motor but if you want guesses, replace the thermostat, the block may need that bit of restriction to keep water where it was designed to go. Clean the carbs, any built-up deposits in the main jets will cause it to run lean and therefore hot. If you're operating in salt or brackish water, you may have salt build-up in the cooling passages, I hear there are products out there for cleaning. Make sure you have the correct heat range plugs. If it idles and otherwise runs fine, I doubt it's a head gasket but it's easy to verify with a compression check. What is telling you that it overheats at speed?

 

[rolandfrank]

Re: dt65 over heating

the motor starts to throw steam out of the water discharge. If I back off and let it idle it cools down. it runs in salt water most of the time. I would think a missing thermostat would make it run too cool..
btw did not see a lot of build up inside the head as far as I could tell thru the thermo hole.

 

[mphelle8vld]

Re: dt65 over heating

I think everyone has heard from their grandfather that removing the thermostat from his 58 Ford made it run cooler since the thermostat controls the amount of water that is directed into the radiator. Your outboard does not have a radiator, the thermostat, when closed, keeps cooling water away from a narrow cooling strip that travels down across the area of the plugs, causing it to heat up quickly. When the motor warms, it opens allowing water through. If the thermostat is completely removed, there might be so much flow allocated to that narrow strip around the plugs that you may be losing flow around the cylinders. It's just a theory but I'm pretty sure Suzuki designed the cooling system to work with a thermostat. Most of the other suggestions are pretty easy to check, let me know what you find.

 

[stylesabu]

Re: dt65 over heating

sounds like this motor is new to you? what if previous ower had an overheat problem, and he first removed t-stat but that didn't help,then he replaced water pump(why it looks new), didn't put t-stat back.found that it still overheated, gave up and got rid of the motor/boat? but what if water pump impeller was bad and the source of the overheat.put it back to oem then do your trouble shooting, every part on that motor is there for a reason

 

[rolandfrank]

Re: dt65 over heating

thanks guys.. yes a new used motor .. ok will have to find the right thermo in ebay or someplace.
makes sense..

 

[stylesabu]

Re: dt65 over heating

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