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My 1987 Suzuki dt140 has a cooling issue at the rpms go up and it stops "peeing" and starts smoking. I have replaced the thermostat and checked the water pump and all looks fine. The last issue I can think of is a bad poppet valve. I have spent hours but can't locate it. Any help would be great. Thanks
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Sounds like you have a problem with exhaust blowing back into the water pump supply chamber under the water pump.
Does your motor have the sub water pickup tube assy?
the sub water pickup tube has a grommet that seals the water pump supply chamber from the exhaust chamber. If this grommet is loose or burnt out it will allow exhaust pressure to interfere with the water pump pulling water in. the higher the RPMs the more the exhaust interferes.
It is an inexpensive repair, but the lower unit has to be off to correct this problem.
Post back and let us know. -
What would the sub water pickup tube assy look like?Originally posted by Solarman View PostComment
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It should be a stainless tube/ pipe, that goes from under the water pump across the exhaust chamber, to a pickup screen just in front and above the prop. This tube adds additional water off the high pressure side of the prop when at higher RPMs.
You can try the below URL? Item #15 is the sub water tube. Item #13 is your grommet (probably your main problem) + item #17 (if available?). Some motors had an option for item #42 (blocks sub water tube - eliminates it?), and item #45 a different option (not sure why these options- what reason?). See URL, below if able?
http://www.brownspoint.com/store/pc/...il.asp?ID=6247
Post back.Last edited by Solarman; 08-25-2015, 11:51 AM.Comment
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Could this be the issue by air going through the bend of the metalComment
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No, (it does look like something is not right there) but that tube going under that plate is the sub-water tube (shine a good light under the red mark you made and re-take the pic, maybe we can see the s/s heat shield). Where that tube goes through the housing under the water pump, there is a grommet that seals the tube to the wall. If that grommet is not sealing, then exhaust will leak into that area under the water pump and interfere with water getting into the pump to cool the motor.
If you remove the water pump housing and the key in the driveshaft (for impeller), you should be able to lift the stainless plate off the bearing cap housing. Then you may be able to shine a light into the cavity, and may see the sub water tube. But, before taking anything apart, get the parts you need for the repair.
That blackened, sooty chamber is the exhaust chamber. If the webbing (cross-section of aluminum) in the midsection, that mates with the webbing in the lower unit are corroded and eaten away, not providing a good seal when bolted together, this can also cause exhaust leaking into other chambers.
Good luck. Post back any questions.Last edited by Solarman; 08-30-2015, 11:52 PM.Comment
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