120HP/400 Stringer cooling problems

Hey gang. I hope you don't mind a long post too much. Today was my first time working on a marine engine/drive and I have all kinds of questions rolling in my head

I put on a set of muffs over the vertical holes below the anti ventilation plate. I'm hoping this is the right spot for the water p/u. After starting the engine, I was expecting to see water streaming out from somewhere, but did not.

I shut it down and after thinking about it decided that it may take some time to fill the cooling system.Started it again, but still did not see anything and shut it down before the temp gauge got to high.

I read in my manual that you will not see any water return if the thermostat has not opened, so started again and let the temp come higher.-no luck. I did notice that for a short time there was a fair bit of black water that started coming out by the prop shaft.

I wondered if the water supply was not working properly,so I submerged the drive in a barrel up to the anti ventilation plate-no luck.

I saw in my manual that it says to make sure the water is coming up through the pivot points.Not sure how to check this so I pulled both covers off and started it again to see if water was coming through-(nothing). I also pulled the 2 lines that go to the front of the exhaust manifold and the one that goes to the exhaust elbow.(no water)

I think that all of this would mean that the lower water pump is not working.I'm just wondering if anyone has anything to add as to what else I might check or do different before tearing into the stern drive.Also wondering where I should see the water return from and what about the water coming from the prop shaft?

Sorry for the length.

what year you left that out. Just look at the back of the boat on the transom last 2 numbers will tell us the year.

You serious about working on this setup you will need a manual. Seloc # 3400 in the right hand corner will do. It has a section in it telling you how to read numbers on the drive and motor telling you the year.

Also if you look on the starboard side of the motor you will see a number stamped on the block. or if you pull the valve cover you will see a year stamped on the head.

The reason i keep harping on the year is there is different places for you to see water peeing ether on the ball gears, how to hook up water to the drive, and what drive you really have.

Post back the year we will go from there.

You have a pm.

Thanks chief. I do have the manual. I'm pretty sure that the drive is a '78. The boat is a '78. The last 2 digits on the engine block are '77. I have read that '78 was the first year of the 400/800 drives, and mine has a 400 plate on top.

I found a drawing that clearly shows the water p/u. I'm still looking to find an answer to where the water should exit. I read in the manual that the exhaust exits out the prop. Should this be just fumes or mixed with water? I have started tearing apart the stern drive and want to know if there is anything else I need to look at, aside from the water pump.

jimmmy said:

After starting the engine, I was expecting to see water streaming out from somewhere, but did not.

Click to expand...

with the muffs on, and hose on full, you should see water pouring out the prop and intermediate grate before even starting the engine.

jimmmy said:

I submerged the drive in a barrel up to the anti ventilation plate-no luck.

Click to expand...

that's not deep enough. The way the OMC pump was designed, the entire drive must be submerged. before it pulls water at start up- like this:

I would just change the impeller - that should be done with any used boat, and it sounds like yours is not pumping - if it was, you may have cooked it running it dry. A new impeller is only $20 or so, but if you live where it snows, buy the whole kit with the impeller hsg. - yours may be cracked from a winter with the drive tilted

when you have the pump running good then you should see a stream of water peeing on the ball gears.

Never run this drive except fully down. And never run it without water going to the drive.

Thanks for the replies.

hystat said:

with the muffs on, and hose on full, you should see water pouring out the prop and intermediate grate before even starting the engine.

I did not have the water on full. I read that you should'nt. The only water that I saw was spraying out around the muffs. Would this mean a blockage?

I'm not sure what to do now. I have the stern drive apart (except the lower unit). The water pump apears to be ok.I'm not sure how it should look, but I don't see any cracks in the housing, and the impeller looks to be ok. So far I have not seen any blockage.




that's not deep enough. The way the OMC pump was designed, the entire drive must be submerged. before it pulls water at start up- like this:

Click to expand...

I guess I need to work on replying with a quote. Hope it makes sense.

See how the tips are bending, what direction. Well if i were you i would replace the impeller, make sure you the impeller tips are bending the same direction.

when you put the pump back together use plenty of permetex make sure the thru bolts are also sealed and the outside of the pump where it meets the metal use plenty there also.

When you start the motor again with the muffs make sure the water is peeing on the ball gears and the drive is fully down.

Water should flow out of the middle of the prop and maybe alot out where the drive and the intermediate meets the exhaust tube.

If not water should still be peeing on the ball gears.

Post back we will go from there.

the hose should be on full, and you are correct - if it was spraying out the muffs on half, there might be blockage. (exhaust riser maybe)

You got to the w/p just in time because your w/p shaft splines are lacking grease. You need a marine grease on them. Once they get dry and rusty like that, they aren't long to failure.

So, I need to figure out what parts to replace before I go ahead. I will get a new impeller. Does any one have part #'s for some of the seals? Also the outer splines on the w/p shaft are not in good shape. I'm not sure if I should let it go for now? Can you buy a new shaft, or would a new water pump come with shaft?

you have a pm

I'm going to put everything back together so I can give the boat a water test before winter, then take the stern drive back off and do a rebuild over the winter. I've seen some other parts not related to the water pump that will also need work. I put the muffs on with the lower unit still removed from the upper and the water flows freely. I think that the real problem with not getting any water flow was my testing procedure.

Chief- you mentioned above to use permatex. Is there a specific permatex product that you use? Do you use it on everything? For example I noticed that there was a heavy layer of silicone where the lower swivel comes up through the exhaust housing. Is this what you would use there as well?

blue. yes.

With the drive up notice a zerk inside the hole on the front of the drive ?

You got the whole thing apart right now, why not do the pump and all with the kit i pointed out to you.

http://www.permatex.com/products/Au...ensor-Safe_Blue_RTV_Silicone_Gasket_Maker.htm

Thanks Chief. You and Hystat have been a real help with learning this stern drive.

I ordered a pump and should have it tomorrow. It is made by Sierra. How do you feel about the Sierra parts?

I will need some gear oil and grease. The manual suggests OMC products. Can you still buy OMC lubes? IF not, or if not at the local dealer, what oil would you guys suggest?

I use wally world gear oil, buy it in the gallon jug. 80-90 weight blue bottle. Tech something. 12 dollars a gallon. My friends use merc stuff, or evinrude stuff, or quicksilver stuff.

You will need a pump, wally world has it also.

All parts are now aftermarket cause the co. is out of bus.

Ask 100 people in a room what oil or oil filter they use and you will get 200 different opinions.

But consider this i am on my 7th year with this boat. Same setup as yours same year stuff. I bought the boat from the original owner, and he's a good friend, and the stuff he used from new was on a list he gave me, everything was the cheapest stuff he could get his hands on. Was no wally world in 86' but k-mart stuff.

Stay with 30 weight oil, and 80-90 weight gear oil, brand and price your choice.

Thanks again for all your help. I put everything back together last weekend with new water pump.Put the boat in the water for my first test run. Everything worked great. I think I will take the stern drive back off for the winter and do a little more work. The shift cable is not in great shape, saw a seal that should be replaced on the swivel assembly, and have water in the lower gear case.Does anybody know if I can still buy a shift cable? I saw an electric one on the net, but mine is not electric.

the shift cable is in stock here at marineengine.com

oh hy i didn't know that. You don't need to completely take apart the whole lower. You need to replace the seal behind the prop and th seal at the top. They are actually 2 back to back. both of them.

And make sure the plugs have new plastic washers. Actually i would pressure test the drive with the oil in it to see where the oil comes out, might just be the plugs.

The seal at the top. Is this the upper seal on the lower swivel unit where the water pump would slide into? I thought about changing it when it was apart, but I was not sure if it just pops out from the top. I was afraid that if I started digging at it , I might find that I would have to take apart the lower case.

got a manual ?

Good one Chief. When I had it apart, I looked at the manual to see about repairing the lower unit. When I got to a part where it talked about needing special tools, I closed the book and decided to leave it alone. Maybe next time I take it apart I will have to open my mind a little and read further into the manual.