help with omc stringer 400 water direction and pressure

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

yes. madness indeed. If i had fabd my own mani's i would still have ported the lower section by the ih and returned the used water to here to meet with the exhaust gases.

The weird thing is the ports both look factory and i can even see two ports in the manual schematic for the ih.... if you look closely.

Did the original exhaust manifolds allow any cooling water to exit with the exhaust? Or did all the cooling water exit the rear fittings in your diagram?

 

[badman]

Re: help with omc stringer 400 water direction and pressure

Did the original exhaust manifolds allow any cooling water to exit with the exhaust? Or did all the cooling water exit the rear fittings in your diagram?

No, as in my refabs, the water exist the manifolds via a separate port at the end of each manifold.
I have a sneaky feeling the weird use of the flushing port was done to bypass a problem or perhaps solve the manifold issue.
Perhaps they plumbed the flushing port through the transom to connect with the manifold on the right...
That way the drive would still be cooled and both manifolds would be receiving cooling water.
This would then make its way into the t stat and through the engine.
It would pass out the engine water pump and out the second port in the transom (side actually) or out the strange second port on the ih which leads to the ih exhause chamber and away.

will test all this later on and tomorrow.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

Right.
Further tested the drive and intermediate this afternoon evening.
I now know why the prev owner was using the flushing trunion fitting.....
The intermediate housing water channels are compromised. The two port type is used in V engines (see manual) and is supposeed to route water from the trunion fittings on the out drive to hoses on the engine/manifold.
On mine, when water is poured in it comes out the exhaust out... and when the engine is run exhaust gases come out the said ports.
This confirms what i saw months ago when i inspected the IH internally... That there is a tear/hole in the internal structure.

So, this means that any water coming up from the drive will not take desired route and travel under impeller presuure through the engine etc. It will take the easy route and run down through the tear and back out the exhaust out.

So, i will block the left trunion fitting so it passes no water.
I will allow water to cool the drive as normal but use the flushing cap to take it away from the top of the drive and through the transom.
I will use a splitter to send it through both mani's and a combiner to bring it together and into the bottom of the engine.
It will then come back out the top of the engine T stat (unlike a marine engine, this engine has water flow like a car... in the bottom cold and out the top warm).
I will then pass the water into the failed Intermediate Housing to escape from the system and also cool the IH/ewxhaust area.
Job done.

The drive elements and impeller are fine and i have cleaned these up and greased them.

I will put gear oil in the upper gear housing and close it all up for a fresh test.

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

..... The two port type is used in V engines MUST BE AN EARLIER ELECTRIC SHIFT INTERMEDIATE HOUSING THAN I HAVE EXPERIENCE WITH. MINE IS A '75 VARIETY V-8 AND ONLY HAS THE ONE OUTLET ON THE TOP REAR OF THE IH HOUSING (see manual) and is supposeed to route water from the trunion fittings on the out drive to hoses on the engine/manifold. SO WHAT YOU ARE SAYING IS THAT WATER PASSES THRU EACH TRUNION CAP AND WAS MEANT TO FEED EACH SIDE OF THE V MANI'S?On mine, when water is poured in it comes out the exhaust out... and when the engine is run exhaust gases come out the said ports.
This confirms what i saw months ago when i inspected the IH internally... That there is a tear/hole in the internal structure. IS THIS FROM CORROSION? A SALT WATER UNIT? COULDN'T YOU HAVE IT WELDED? UP?
So, this means that any water coming up from the drive will not take desired route and travel under impeller presuure through the engine etc. It will take the easy route and run down through the tear and back out the exhaust out.

So, i will block the left trunion fitting so it passes no water. I THINK THAT IS THE NORMAL PATTERN IN LATER ELECTRIC SHIFT INTERMEDIATE HOUSINGS. THE PORT TRUNION CAP DOES NOT PASS WATER IN MY UNIT. I will allow water to cool the drive as normal but use the flushing cap to take it away from the top of the drive and through the transom.
I will use a splitter to send it through both mani's and a combiner to bring it together and into the bottom of the engine.
It will then come back out the top of the engine T stat (unlike a marine engine, this engine has water flow like a car... in the bottom cold and out the top warm).
I will then pass the water into the failed Intermediate Housing to escape from the system and also cool the IH/ewxhaust area.
Job done.

The drive elements and impeller are fine SO THE IMPELLER IS PUMPING UP A STORM? IT JUST WAS NOT GOING WHERE IT SHOULD? and i have cleaned these up and greased them.

I will put gear oil in the upper gear housing and close it all up for a fresh test.

Sounds like you will be a real expert when you are done. Do you think there are many of these old OMC units in the Isles?

 

[badman]

Re: help with omc stringer 400 water direction and pressure

Originally Posted by badman Vie
..... The two port type is used in V engines

MUST BE AN EARLIER ELECTRIC SHIFT INTERMEDIATE HOUSING THAN I HAVE EXPERIENCE WITH. MINE IS A '75 VARIETY V-8 AND ONLY HAS THE ONE OUTLET ON THE TOP REAR OF THE IH HOUSING
Possibly. My drive looks to be pre 67 and is the four bolt type.
The ports access the same chamber so it looks to be just the port top plate which was interchangeable.
(see manual) and is supposed to route water from the trunion fittings on the out drive to hoses on the engine/manifold.

SO WHAT YOU ARE SAYING IS THAT WATER PASSES THRU EACH TRUNION CAP AND WAS MEANT TO FEED EACH SIDE OF THE V MANI'S?

Well, this is where it's a bit odd. It looks as though only the port side trunion feeds a water channel into the IH. The starboard trunion also has the cavity but is blocked. Either they prev owner blocked it or its factory blocked in the IH side channel. I cannot see inside its too deep in the IH.
On mine, when water is poured in it comes out the exhaust out... and when the engine is run exhaust gases come out the said ports.
This confirms what i saw months ago when i inspected the IH internally... That there is a tear/hole in the internal structure.

IS THIS FROM CORROSION? A SALT WATER UNIT? COULDN'T YOU HAVE IT WELDED? UP?

It was really hard to tell, water just seemed to pour down from the inner top of the IH and this implies a corrosion situation in the base of the IH top dual ported water chamber. At the time we didn't know our *** from our elbow so it was just one more oddity. It would have been a serious wed job, not only because it is cast aluminium (TIG), but mainly because the whol Floor mounted IH and boot would have to be removed to access the top water chamber with ports etc. (Thats just given me an idea..... take the rear wooden crossmember off and i should be able to access it for a visual).

So, this means that any water coming up from the drive will not take desired route and travel under impeller presuure through the engine etc. It will take the easy route and run down through the tear and back out the exhaust out.

So, i will block the left trunion fitting so it passes no water. I THINK THAT IS THE NORMAL PATTERN IN LATER ELECTRIC SHIFT INTERMEDIATE HOUSINGS. THE PORT TRUNION CAP DOES NOT PASS WATER IN MY UNIT

Yep. ok.
. I will allow water to cool the drive as normal but use the flushing cap to take it away from the top of the drive and through the transom.
I will use a splitter to send it through both mani's and a combiner to bring it together and into the bottom of the engine.
It will then come back out the top of the engine T stat (unlike a marine engine, this engine has water flow like a car... in the bottom cold and out the top warm).
I will then pass the water into the failed Intermediate Housing to escape from the system and also cool the IH/ewxhaust area.
Job done.

The drive elements and impeller are fine SO THE IMPELLER IS PUMPING UP A STORM? IT JUST WAS NOT GOING WHERE IT SHOULD?

Tomorrow i will check my repair/service work and reinstall the drive parts and run it up. Today i was STILL repairing /painting a repair trailer for a customer.
Even though the impeller and seals were full of salt and some corrosion, there looked to be nothing majorly wrong. I cannot at this time see any valid reason as to why the impeller would not pump. Unless the vertical impeller drive shaft keyway was sitting above the keyway in the impeller. The shaft would spin the the impeller would not.
However, i suspect that there is another reason for the lack of water pressure... more acorns in the drive! The boat isn't called DANGERMOUSE for nothing! i saw the mouse once.... a real chubby fella. It had been very resourcefull and had a huge nest by the fuel tank and many food stores. An acorn even came out of one of IH exhaust route.

and i have cleaned these up and greased them.

I will put gear oil in the upper gear housing and close it all up for a fresh test.
Sounds like you will be a real expert when you are done. Do you think there are many of these old OMC units in the Isles?
There are a few of these around. One chap in Norfolk was selling the same drive in factory white on ebay. It went for a few hundred pounds in the end.
Mostly these days its Mercruiser and Volvo out drives.... the same as most places i imagine.

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Do you know if the large seal in between the upper and lower drive sections is needed for any other reason than just to provide a seat for the upper section? initially i thought i was integral to the impeller suction but now i think not.
Secondly, how much gear oil goes into the top chamber with the ball gear shaft and worm drive?
Cheers!

 

[badman]

Re: help with omc stringer 400 water direction and pressure

Okay. Another day on the stern drive and ....

Two problems..
1 Water is getting into the lower gear casing oil, past the seals.
2 There is a 15mm round hole in the impeller housing.

Re: the water/oil... it seems like a bad design to me as the water comes in through 3 inlet holes right to the lower area of the vertical shaft above the lower gear casing.
Right to the same area where the shaft sits on a seal, under which is the oil reservoir.
Any tricks to fix this?

Re: the hole... it is definitely passing water straight back down and out of the drive. Should there be a plug/fitting there?
If not, someone has drilled it and i will have to metal fill it.

Does anyone have experience of re assembling the lower gear casing to upper gear casing?

thanks