Still overheating %3cIMG SRC%3d%22httpwwwmarineenginecomdiscusclipartsadgif%22 ALT%3d%22%22 BORDER%3d0%3e

"Rick;
PN 29 is definitely th

"Rick;
PN 29 is definitely the water inlet hose from the drive. If you have PS, the cooler would be a suspect for plugging.

Please let us know how your backflush test of that hose goes.
Water will not flow by gravity out the manifold, as it must go up and over the riser/elbow. You should however be able to rig your garden hose up to it and get it to flow through under a little pressure. That is a test I would also do so as to rule out a blockage in that area.

Rod

Rod"

"Alright. Update #1 - after m

"Alright. Update #1 - after much struggling i finally got the water inlet house off and ran some water into it. It came out the lower unit.. first through the weephole, and then through the water intakes."

"update number 2 - when forcin

"update number 2 - when forcing water into the manifold, it flows out the back ... by the transom)

So this would seem to imply an issue within the upper/lower unit itself, wouldn't it?"

"None out the prop exhaust ope

"None out the prop exhaust opening? Or at least very little? What about the opening in the front of the leg just above the cavitation plate?

If no major water shows in this area, it sounds like most everything is intact. In this case it has to be something wrong in the pump. The impeller is in wrong, its the wrong impeller, the blades are in the wrong direction, its chewed up, the shaft key is missing, or something like that.

You will have to pull the leg and recheck the entire pump, water tube, & coupler again.
I would do the manifold flow test first to rule that out.

Aren't boats fun?

Rod"

"Rod - I think I did the manif

"Rod - I think I did the manifold flow test, didn't I ("update number 2")

I'm taking the boat back over to my dad's tonight to take the lower unit off again! I'll update later!"

"sorry, left out the pressure

"sorry, left out the pressure part to get over the hump in the riser.
you really shouldnt be able to push water back toward the pump and see it come out anywhere.
I`d still lean toward the water pocket cover, the copper connecting tube,water pump assembly.
To prove the point, being that your taking the lower off,remove the complete unit and do the hose test."

"Alright, here's where we

"Alright, here's where we stand.

All my flush tests performed as expected. Using the garden house, if I pump water into the large host, filling the engine block, the water flows out the thermostat housing after the engine block is filled. If I pump water (under pressure) into the smaller hose that goes into the manifold, the water comes out the exhaust in the transom. If I pump water into the water inlet hose, it comes out the water intake.

"you really shouldnt be able to push water back toward the pump and see it come out anywhere."

Why not? I'm pretty sure when you take the boat out of the water, it's designed so that MOST of the water in the stern drive (water pocket, etc) flows out.

With the lower unit removed, I visually inspected the water pocket cover, it looked fine. I again ran water into the inlet hose, and the water came out the copper pipe - nowhere else.

The impeller looked good. When we re-installed, I made sure to turn the drive shaft clockwise so that the impeller blades are rotated counter-clockwise, as the manual instructed. drive shaft key is in place.

So we put everything back together, connected the ear muffs, and started her up again. Keep in mind that I had previously filled the engine block with water.

It ran for a while. Some water was spraying out with the exhaust, but not much. Hard to tell if water was being pumped in. But the engine started overheating again and I stopped it around 200 degrees.

I immediately removed the thermostat housing to check the thermostat and it was wide open.

Hard to tell if the impeller was pumping water up into the unit. Water coming out the exhaust may have just been bits of the water being "blown" over the riser by the exhaust.

What about my engine circulation pump? I mean, it seems like a very simple piece of hardware. The belt is attached and it looks to be operating normally.

What's the likelyhood that I have a problem with the engine circulation pump? IT seems unlikely as it's not a particularly complex piece of machinery!"

"Regarding the "hose test&

"Regarding the "hose test".. you mean this one:

"You remove the whole drive, insert hose into water inlet hole in gimbal housing for the water pocket, just need to look.
the one in the pic was leaking the water before it got to the engine"

But wouldn't the water then be pumped up into the lower unit and then leak out of the gimble housing/transom assembly?

Also, since I ran water down the inlet hose from the engine, and it came out the copper pipe (while the lower unit was off), wouldn't that also indicated that there is no problem in the gimble housing?

I mean I can try it tomorrow.

If I don't solve this by Sunday I'm taking it to the boat shop Monday and letting them figure it out! Lest I spend the entire summer working on the boat, instead of boating!"

"Rick,
Here is a simple tes

"Rick,
Here is a simple test. Connect a clear hose ( get it a your local home store) and connect it between the oil cooler and the thermostat housing. When you run the engine on a garden hose ther should be a clear flow of water. If there is voids or large air bubbles then the problem lies between the transom assembly and the drive. Since you just changed the water pump, I don't think it lies there. I think the problem lies within the bell housing and the water pockit tube. On the alpha 1 gen 1 the water pocket assembly costs about $16, change it if you have the drive apart. If the drive is off the boat run water from your garden hose through the bell housing and see how the water enter to the thermostat housing through the clear plastic hose. If there are voids then the problem lies in the hose within the bell housing and the transom assembly. These hoses sometimes kink due to age. See this cite for a reference. http://www.mercstuff.com/bellowsreplacement1.htm"

"IT WORKS! IT WORKS!

For n

"IT WORKS! IT WORKS!

For now.. =)

As I said it overheated Friday niight with the thermostat in. Saturday morning, I disconnected the water hose and ran the engine and it is definately pumping water. So I removed the thermostat and ran the engine for 5 minutes. IT ran cold. Didn't overheat.

While I still hadn't tested the thermostat, we decided to replace the engine circulation water pump. After removing it, it LOOKED like it was working fine but we replaced it anyway.

Put everything back together, put the thermostat in, and aside from a leak in the thermostat housing because I need a new gasket, everythign worked great. I removed the thermostat housing one more time and cleaned it thoroughly, then put in some silicon thermostat housing sealant, and then put the housing back on good and tight.

I ran the engine for about 10 minutes and it came up to about 160 degrees aand stayed there.

So it certainly seems like the overheating may have been a symtom of a partially faulty engine circulation pump that the original owner of the boat "solved" by removing the thermostat.

Whatever, it all seems to work now!

I also "installed" the new stereo, so she's now fully ready for the summer."

Great news.
Have fun.
Rod

Great news.
Have fun.
Rod

"Thanks to everyone for their

"Thanks to everyone for their help and suggestions on this matter! I certainly know a lot more about boat engines that I did a few weeks ago (which honestly, was next to nothing)."