Another Cooling Question
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
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- Location: Sherborn, MA 01770 USA
Another Cooling Question
Hello - I'm a new owner of a 1974 Forty Plus, last run in 1985. After cleaning 24 years of crud out of the gas tank, it started on the second pull - a pleasant surprise. However - no water coming from the block at any RPM. A reverse flush with the hose shows a good flow of clean water out of the intake slots and streams coming from the small holes in the chrome shaft housing. No water comes out the exhaust. I took the prop off and tried it again. After a moment or two, at about 1/2 throttle, a small stream of luke warm water appeared. It stopped at a higher throttle, reappeared at mid-throttle and disappeared at low throttle. Then, it was gone entirely from any throttle setting.
There is a heavy residue of very thick greasy oil around the perimeter of the barrel. A small trickle of greasy oil starts to run down the exhaust tube. Lot's of exhaust smoke at high revs.
What should I do/look at next? Overall, the motor seems to be in excellent condition. I see very little corrosion inside the block, when viewed through that water exit hole and little corrosion on the inside of the prop hub. Oh, and the lube in the gear housing was a heavy, very dark fluid. It was not grease because it did drain, and I replaced it with 140 oil.
Sorry to be so long winded - and thanks for any help and guidance. Al
There is a heavy residue of very thick greasy oil around the perimeter of the barrel. A small trickle of greasy oil starts to run down the exhaust tube. Lot's of exhaust smoke at high revs.
What should I do/look at next? Overall, the motor seems to be in excellent condition. I see very little corrosion inside the block, when viewed through that water exit hole and little corrosion on the inside of the prop hub. Oh, and the lube in the gear housing was a heavy, very dark fluid. It was not grease because it did drain, and I replaced it with 140 oil.
Sorry to be so long winded - and thanks for any help and guidance. Al
If you get a good flow out of the water intake slots when you stick a hose on the normal outlet on the powerhead then the cooling system is not blocked.
The fact that none comes out of the exhaust is good because the exhaust is not water cooled and it indicates that the water tube between pump and block, which runs inside the exhaust tube, is not leaking.
In a barrel make sure the water pump is completely submerged. Turbulence cased by running in a small barrel with the prop on can result in little or no water flow but you have tried it without the prop.
Ultimately you may have to inspect the water pump but the impellers do not wear like flexible vane impellers in posher outboards do.
All the oily residue and smoke is pretty normal, especially if you are using a 10:1 fuel mix.
The fact that none comes out of the exhaust is good because the exhaust is not water cooled and it indicates that the water tube between pump and block, which runs inside the exhaust tube, is not leaking.
In a barrel make sure the water pump is completely submerged. Turbulence cased by running in a small barrel with the prop on can result in little or no water flow but you have tried it without the prop.
Ultimately you may have to inspect the water pump but the impellers do not wear like flexible vane impellers in posher outboards do.
All the oily residue and smoke is pretty normal, especially if you are using a 10:1 fuel mix.
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- timberman2004
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- Location: Lerryn Cornwall
agree with Vic
a barrel for running an engine up is never totally ideal ...don't be frightened to increase the depth
in my humble experience well immersed...very well immersed, is not a problem
if you have water flow and it's only lukewarm it's working !!!!
a barrel for running an engine up is never totally ideal ...don't be frightened to increase the depth
in my humble experience well immersed...very well immersed, is not a problem
if you have water flow and it's only lukewarm it's working !!!!
Neal...errrr... an ON, OP, 2xSD, F, 3xSJP, LLS, 2xFV, FVP, FPC, CPC WPCL, WSC, and a few eggs hatching, hopefully
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Hello Vic and Timberman - you must be right on about the depth (or maybe even the shape) of my water barrel. I removed the lower end and everything was very clean - no dirt or corrosion. I easily ran a wire all the way up the water tube, rotated it and pulled it back out clean as a whistle. I put the garden hose against the exhaust end of that tube and got a huge flow of water out of the block - ditto in the opposite direction. There can't be any blockage. The impeller looks to be very good - about 1/32" clearance between the vanes and the housing and perhaps 5/64" up and down movement.
So, back together again tomorrow and another try in deeper water and/or another barrel. Will it be OK if I reuse the same gasket between the lower unit and the pump housing - or should I get a new one? The old one looks OK and came off cleanly. Thanks to both for your help! Regards, Al
So, back together again tomorrow and another try in deeper water and/or another barrel. Will it be OK if I reuse the same gasket between the lower unit and the pump housing - or should I get a new one? The old one looks OK and came off cleanly. Thanks to both for your help! Regards, Al
- Charles uk
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- Location: Maidenhead Berks UK
The rev range of a 40 series motor is from about 2200 to 4000 revs.
the water pump is very unlikley to pump at tickover & probably won't start to pump until 2500 to 2600 revs, when testing in the water tub, open it up a bit & then a bit more.
There seems to be no physical reason your motor should not pump from your description.
the water pump is very unlikley to pump at tickover & probably won't start to pump until 2500 to 2600 revs, when testing in the water tub, open it up a bit & then a bit more.
There seems to be no physical reason your motor should not pump from your description.
- 40TPI
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If it is still in one piece and not grossly de-laminated or cracked it will be perfectly fine. If it makes you feel better spread a little Hermetite around but it should be perfectly fine without; it's not as though we are talking high pressure water.goldengull wrote:......Will it be OK if I reuse the same gasket between the lower unit and the pump housing ......
Peter
Oh no! If it is still in good nick coat it lightly with some waterproof grease. Then you'll be able to use it over and over again. Stick a jointing compound on it and it'll be curtains for it next time you remove it.spread a little Hermetite around
If jointing compound is necessary to seal a slightly damaged gasket apply it to the gasket but grease the surfaces between which it is to be fitted. Then it wont stick.
Same applies to using Instant Gasket on joints you want to be able to break easily. Instant Gasket on one surface, and lightly grease the other.
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Thanks, everyone. I put it back together and set it (still propless) back in the bucket with an inch or so more of water than before and it worked! A nice stream of luke warm water came out at all thottle settings, except the very lowest. You fellows were absolutely right!
The fuel consumption is interesting. I probably ran the motor no more than 15 minutes total, probably closer to only 10 minutes and used up a pint of gas. This means only about an hour for a tankful. Is this right? Al
The fuel consumption is interesting. I probably ran the motor no more than 15 minutes total, probably closer to only 10 minutes and used up a pint of gas. This means only about an hour for a tankful. Is this right? Al
Specifications show the 40+ should use about 1.7 pints per hour at 1/2 to 3/4 throttle so with the standard 4 pint tank you should get around 2 hours, mine certainly gets about this and has to work hard for a living frequently at full chat.
Suggest you look for fuel leaks, pay particular attention to the tap, also make sure the carb isn't flooding due to a stuck or non seating needle valve.
Suggest you look for fuel leaks, pay particular attention to the tap, also make sure the carb isn't flooding due to a stuck or non seating needle valve.
Water problems
Well done everyone putting him right.
Failing to get the pump far enough under seems to be a common problem for owners. Must add a line to the skreed on the FAQ page about it all!
Regards,
John
Failing to get the pump far enough under seems to be a common problem for owners. Must add a line to the skreed on the FAQ page about it all!
Regards,
John