AD-12 overheating – new impeller too!!

[63lstrition]

This is a project that my girlfriend and I have been working on. Its now her baby!! Had a buddy come over and fine tune the carbs for me. As we were doing that we noticed that there was not much water coming out of the exhaust and it was getting hot. We shut it down to try to figure things out.

Here is a video of it running. –
https://m.youtube.com/watch?feature=em- … 7yTfh6swZ0

Is there another telltale besides the exhaust? Can anyone tell by looking at it if it seems like it is pumping at full volume?

Any suggestions? Is there a way to blow out the passages without taking off the powerhead?

[fisherman6]

It’s hard to tell from that distance, but it does look like the pump output is a little bit low. You say it has a new impeller. When it was replaced, did you rotate the driveshaft in a clockwise direction as the pump housing over the impeller? Just trying to verify that the vanes aren’t backwards. If the flywheel gets rotated backwards, even a partial turn, it can turn some of the vanes backwards and reduce the output. Of course, as you know the only way at the impeller is to pull the powerhead on these motors.
-Ben

OldJohnnyRude on YouTube

[retiredoz]

Looks like a lot of roiling water in that bucket too. Probably wouldn’t hurt to add some.

[frankr]

That motor might (probably) have a restrictor in the water tube. It might have a chunk of crud in it. Also, the slanted hole in the water pump housing, between the water tube grommet cavity and the cup around the drive shaft might be plugged up. The purpose of the hole is to keep the cup filled water, which acts as a seal around the drive shaft hole. That will cause erratic pumping if plugged

And of course you are running it in a tub, which may be ok (??)

[chinewalker]

Can be dicey running in a small bucket as the water gets very aerated. Pump ends up sucking a fair bit of air with the water.

[63lstrition]

it was a 40 gallon garbage can. Probably just too high on the stand and not deep enough in the can. I will try lowering it, but I ran 3 motors this morning and 2 of them overheated while one did not. I am thinking it is less to do with the bucket and something with the cooling circuit.

[crosbyman]

the impeller should rotate itself in the right direction even if put in backwards. try it on the lake instead of a bucket

impeller key OK ??

Joining AOMCI has priviledges 🙂

[johnyrude200]

A few questions to get to the bottom of this issue….

1. What are you using to figure out the motor is overheating?

2. The video is hard to really tell what’s going on. We need some temperature numbers to confirm an overheat. There is clearly water coming out of the exhaust relief hole/blubber hole. The motor should be pumping water like a fire hose; it doesn’t have a thermostat.

3. Running motors in garbage cans leads to A LOT of false positives. If you are going to do this as a hobby with any regularity, and have 12 square feet, get yourself a 275-gallon tote and convert it into a test tank. It makes a huge difference. It is also (depending on how you customize it) reasonably close to the original test tank minimum requirements.

4. What you say "it was getting hot," what are you referring to? The exhaust housing? The water output? The powerhead? Where on the powerhead? Temperature readings, IMHO, should be at the SB cylinder sides (where applicable) and the top of the #1 cylinder (heat generally rises); or at the thermostat cover and thermostat orifice (where applicable).

[ERROL STILLINGS]

Understand your reluctance to pull the powerhead – but – have you checked the head gasket? With the powerhead removed you can also check the
crud buildup in and around the head. A head gasket that is "going" or "gone" …..

[mad-man-bill]

don’t forget little hole on top of impeller housing bleeds air out that’s got me a few times

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