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Trouble with overheating. I have been thru everything from gimbal to Tstat housing. New T stat 140, clear oil cooler, new aluminum headers. I have forward flushed and backward the entire circuit with garden hose with the drive off. I will now test the flow from drive and run the engine on a garden hose. The overheat occurs at idle-1500 rpm.
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Usually a low speed overheat is caused by the impeller. You have probably checked it, but if it has run through some sand, it will cause ridges on the end of the blades and cause a loss of efficency at the lower rpm's and cause an overheat. If you had an issue with the engine, such as sand in the block, or plugged up manifolds, I would think it would be a high speed overheat.
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How much Water flow?
Got an estimate from Mercruiser that water flow should be about 15GPM. Measured my 106 drive and I am only getting 8gpm at idle??
Can you tell me what pump is in the 106 drive as Mercruiser uses a hi pressure, low volume pump in old model Gen l and a lo pressure , hi volume pump in Gen ll. and Bravo.This makes a difference in what thermostat housing is used?
The engine is new with only 40 hours on it. Never been in sand and the SEI drive has never been off the lift because of the overheat problem.Comment
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How much Water flow?
Got an estimate from Mercruiser that water flow should be about 15GPM. Measured my 106 drive and I am only getting 8gpm at idle??
Can you tell me what pump is in the 106 drive as Mercruiser uses a hi pressure, low volume pump in old model Gen l and a lo pressure , hi volume pump in Gen ll. and Bravo.This makes a difference in what thermostat housing is used with which pump.
The engine is new with only 40 hours on it. Never been in sand and the SEI drive has never been off the lift because of the overheat problem.Comment
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15 GPM sounds too high. I don't think you'd get 15 GPM out of your garden hose. Our SE106 pump is the same style as the OE pump. When you put a new engine in it, did you buy a complete engine with the thermostate housing and hoses? There is definately a difference it the water routing from the old engines to the new engines. Anytime someone was putting a new complete engine with an old drive, Mercruiser would recommend installing an engine mounted water pump.
Tech SupportComment
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How much water flow ?
I am Still not sure which OEM pump you use withoout taking the unit apart. Do you have an optional Merc part number for the pump in a SEI 106 drive?
I installed the engine as it came. It was taken out of a running boat. I did not change the piping.Comment
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This is the style pump: http://www.sterndrive.cc/mm5/merchan...ory_Code=106WA
If you are looming for a replacement, just tell the parts guy it is a 1983-1990 alpha one. I don't have the part number handy, so I can't give it to you.
What year boat is the motor out of? If it is 91 or newer, then you may have the water routing problem.
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temp
I read your post as having 40 hrs on the motor and the drive,is this correct?
Did you have a temp issuse from day1?
Did it ever run properly?
Inspect the engine circ pump for a broken shaft, requires removing the back plate.
5 seconds without water is enough to damage the impeller.Making sure it will start without water is enough time for damage.If this started from a pump repair make sure the base gasket is not reversed.There have also been a batch of defective impellers , the rubber spinning on the insert. Dont know where SEI gets theirs from but I have 8 so far from Sierra and know of 6 from Mercruiser.Comment
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How much water flow ?
I'll try to clarify.
I replaced an old '88 350 Magnum engine with a "used" engine that had 40 hours on it. It had been rebuilt but did not satisfy the owner who pulled it out and replaced it with a Big Block set up. It came complete with manifolds and piping just as it came out of the boat. It did not come with the drive. I decided to hang on a new drive (SEI 106) to match the new motor.
That gets us to minutes for the drive and 40 hours plus minutes for the motor.
All tests were made on a boat lift, in the water, not on muffs.
OK,just found specs,SEI 106 uses Gen 1 pump. Lo volume.Comment
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Did you just replace the long block, or the complete engine? What year boat did the replacement engine come from?
Checking the pump is a good place to start, but if you have the hose routing set up for a 1991 or newer, then that might be a problem.
Tech supportComment
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How much water flow?
I can't explain any more clearly than the motor was taken right out of a running boat after it had been rebuilt.It was not rebuilt after it was taken out of the boat. It was not a "long block", it was a complete motor ready to run. Alternator,carb,headers,starter,hoses etc. I Installed it in my boat and hooked up the water, battery and gas and it was a go.
Since this looked like a flow problem, The original question was how much water should the SEI drive deliver ? Yesterday I solved the problem. It was the application.Thanks everyone for trying.Comment
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How much water ?
Found the problem. The "Complete" motor came with the wrong thermostat housing. Piping and hoses had nothing to do with the overheat. They are connected the same.Comment
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How much water flow
I didn't see my last response posted ?
It was a complete motor. Everything mounted on it, ready to hook up and use. I Attached your SEI 106 drive to the engine and it overheated. After going through a lot of elimination work I found that the thermostat housing did not match the pump characteristics of the SEI 106 drive pump. I changed the theermostat housing and now no overheating.Comment
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It sounds like it was a motor from a 1991 or new boat, which will use a different routing of the cooling water. Changing the thermostat housing to the old style makes sense, since now it will flow the same as the old motor.
Tech SupportComment
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How much water flow
A Bravo and an Alpha thermostat housing.Comment
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