help with omc stringer 400 water direction and pressure

[badman]

hi all.
i really need to know the direction of water flow in a400 stringer omc outdrive.
Does it come up through the lower casing, up through the top of the drive, split half into and through the intermediate and the other half out the 1 inch pipe at the top right side of the drive ocean-side and then through the transom etc?

The reason i ask this is that i fear my impeller isn't working and want to put a water pump inline and need to know the correct flow direction.
I really don't seem to have much water flow and have flushed the rig and there is no blockage.

It could be that testing the flow with the drive in a tub of water is not allowing the propeller and the water pressure which would be there if the boat was moving forward, to push water into through the drive casing and up throughout.
i imagine this water pressure would then prime the drive with water and allow the impeller, now submerged in water, to do it's thing.

thanks in advance and conratulations for reading all of this!

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

I would be suspect of the test results from having the outdrive in a 'tub' of water. Seems enough cavitation could occur, keeping sufficient water out of the pickup ports. Even running on muffs (mickey mouse ears), I would be hesitant to trust the results because water pressure from the hose might skew the results.

All that being said, the water is pumped up from the outdrive, into and thru the intermediate housing and out the single fitting on the top of the intermediate housing. From there, the attached hose would go to a 'tree' on the thermostat housing were it is distributed a)to the motor, b) out to each of the exhaust manifolds.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

Thanks for the reply.
Oh. Somethings not right then.
I have attached a basic diagram of the setup.
Blue squares are ports for water hoses.

The T stat does have a tree with only two hoses and the port going into the engine (the t stat housing).

I have a feeling that the water plumbed the wrong way here.

What do you think?
Based on the diagram what should connect to what?
Sorry if i am sounding thick but we thought we had it worked out but it seems totally different.... which is fine because nothing was connected when i got it.

many thanks

 

[badman]

Re: help with omc stringer 400 water direction and pressure

one more thing...
i have found a picture on the net showing the hoses coming out of the intermediate (2 ports), and going into the manifolds.
out of those and into the t stat tree (2 ports) through the engine and out the water pump, transom, back into the stern drive and out.

sound right or wrong?
thanks

 

[Howard Sterndrive]

Re: help with omc stringer 400 water direction and pressure

your drawing is of a vee engine.
but a 400 series only goes behind 4 cylinder engines.

What engine do you have?

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

your drawing is of a vee engine.
but a 400 series only goes behind 4 cylinder engines.

What engine do you have?

Badman has an old electric shift (I think low profile) of an undisclosed year, mated to a European V4 Ford? engine. A Brit, he is.

Badman's diagram shows a version of the electric shift intermediate housing that pre-dates my experience. I have a mid 70's electric shift intermediate housing that was mated to a V8. It only has one cooling water feed fitting on the top rear of the housing. I'm sure his two eminate from the same plenum in the IH but would have no idea how they were plumbed to the engine unless each one went to seperate manifold and then were T'd up to the thermostat housing assy.

Also, my exhaust manifolds did not have any rear exit plumbing for the water. All water entering the exhaust manis exited, at the rear, thru the risors, combined witht he exhaust.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

thanks wizeone for the informative assistance.
Yes it sems the IH is a two port type.
If it was a one port like yours, does water flow out of the top port or into it?
also, ocean side of the transom, does water flow into the port/pipe at the top right of the drive or out of it?
if i know this i can jury rig the rest!
thanks again

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

......If it was a one port like yours, does water flow out of the top port or into it?....

The water flows up from the outdrive, out the pivot trunions, into the ocean side of the of the intermediate housing, thru passages in the trunion cap(s), esp, starboard side, then into a plenum chamber below where the fitting(s) are.

From the construction of the intermediate housing, I would have to say, even with your two fittings, they eminate from the same plenum chamber and water only ever goes in one direction from them, ie, up and out. Never down. All cooling water exits along with the exhaust.

The pickup tube for your outdrive water intake should be directly forward of the exhaust outlet. This should not be greatly affected by running the outdrive in a tub, especially at an idle.

For a quick test, pull off the starbord trunion cap and run the engine. You should have a steady, uninterupted flow of water out the cap end. If not, either the impellar is bad, the pickup tube is dislodged or the after impellar passages are blocked.

I just would not have a clue how your lines would be plumbed to the engine, after the water leaves the top of the intermediate housing. Maybe some one has a manual from the '60's?

 

[Kovah55]

Re: help with omc stringer 400 water direction and pressure

There should be a " tattle-tale" Steam of water 2 actually out the back of the drive high up. If no streams no water is being pulled into the drive.
A new impeller should be installed.

 

[badman]

stringer 400 water direction and intermediate

stringer 400 water direction and intermediate

ta for the reply again.
Now i am worried.
I have attached some pics to show the IH inside, right side with pipe and a pic of the manual page for o ring and impeller region.

On my drive the o ring which is sort of visible halfway up the drive, is flat and moves about with a gap. Does this mean its ruined?
I f so, how do i open this can up to inspect and replace?
A scan from the relevant page of the manual would show me?
I think i would have to undo the 6 or so bolts holding the drive top cover and then somehow undo the upper casing.?

Next question.... what is the pipe at the starboard side of the drive for?
Does water come out of there?
Is it standard? it looks factory.

When i ran the drive submerged, water was trying to come out of the ports at the top of the IH but was struggling.

I now think that this is because the impeller is unable to pull water up due to the failed o ring.

Anyone know a price for one?
Does anything else have to be replaced at the same time?

Many thanks

 

[Kovah55]

Re: help with omc stringer 400 water direction and pressure

There is now at the top of the forum, in the Adult only section a manual that you can d/l.
To your question, that pipe ain't standard, and never saw that setup in my life.
You can buy the whole water pump kit, with housing at ebasicpower.com.
You can also buy a kit for the upper, with all new gaskets also at the same site.
There was a a post i will try to find it about how to replace the water pump.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

great.
thanks
downloading today.

 

[Kovah55]

Re: help with omc stringer 400 water direction and pressure

Ok found the post, this guy Chief Alen seems to know a hell of alot about stringers.
Here is his post.
http://forums.iboats.com/forumdisplay.php?f=21

 

[badman]

Re: help with omc stringer 400 water direction and pressure

There is now at the top of the forum, in the Adult only section a manual that you can d/l.
To your question, that pipe ain't standard, and never saw that setup in my life.
You can buy the whole water pump kit, with housing at ebasicpower.com.
You can also buy a kit for the upper, with all new gaskets also at the same site.
There was a a post i will try to find it about how to replace the water pump.

Hey thanks for this info and link.

Browsing the manual now and it's a BIG help.
Doesn't look like the drive i have is even the one pictured! maybe a later type omc. looking into it now with the later type manual.
thanks again

 

[WizeOne]

Re: stringer 400 water direction and intermediate

Re: stringer 400 water direction and intermediate

Next question.... what is the pipe at the starboard side of the drive for?
Does water come out of there?
Is it standard? it looks factory.

The water from the impellar normally goes up and out of the OD thru that starboard trunion cap. Someone has removed the cap and fashioned a hose fitting and piped it back thru the transom. Where does that flexible pipe lead to on the inside of the transom? I really doubt this is 'factory'. That is the 'cap' I said to remove when the engine was running to see if a copious stream of water issued forth.

Normally the end of that trunion has a solid cap on it just like the port side. This is also where you would install the optional flush adaptor. When installed with a garden hose hooked to it, it would send water down to the impeller as well as up to the engine.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

well after reading some of the manual it looks like the previous owner left the flushing fitting on the trunion cap and ran a hose from it through the transom.
I connects to the engine water pump.

Seems a bit mickey mouse to me?

I think because the manifolds don't combine the water out from the engine with the exhaust out, the owner had to find a way to get the used water out and devised this idea.

Either that or someone just had no clue and guessed it.

Tomorrow i will certainly submerge the drive and remove both trunion caps and run the engine to see if there are any streams of water.

If not, i will attempt to remove the exhaust housing top cover and then remove the upper casing with water pump to check for defects.

I have a sneaky feeling the bolts aren't going to want to budge as i sheared one off some time ago somewhere else on the drive ( the tilt quadrant mount).

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

.......as i sheared one off some time ago somewhere else on the drive ( the tilt quadrant mount).

Ooh, I wish that you had asked your bolt removal question before you tackled those. I hope you were able to get the broken remnants out?

 

[WizeOne]

Re: help with omc stringer 400 water direction and pressure

well after reading some of the manual it looks like the previous owner left the flushing fitting on the trunion cap and ran a hose from it through the transom. It connects to the engine water pump.

I think because the manifolds don't combine the water out from the engine with the exhaust out, the owner had to find a way to get the used water out and devised this idea.

So, they hoped the normal water path would cool the manifolds and the by-pass (from the flush adaptor) would cool the motor? Where would the return from the engine be dumped?

This would be quite foolish, IMHO, as allowing water out of the flush port would bleed off sufficient water to cool the exhaust manis. I'm beginning to wonder if that second IH port was scabbed in by a previous owner, thinking he would plumb one each to each of the exhaust manifolds? But your diagram seems to show a rear water exit from the mani's that do not go out with the exhaust?

 

[badman]

Re: help with omc stringer 400 water direction and pressure

So, they hoped the normal water path would cool the manifolds and the by-pass (from the flush adaptor) would cool the motor? Where would the return from the engine be dumped?

This would be quite foolish, IMHO, as allowing water out of the flush port would bleed off sufficient water to cool the exhaust manis. I'm beginning to wonder if that second IH port was scabbed in by a previous owner, thinking he would plumb one each to each of the exhaust manifolds? But your diagram seems to show a rear water exit from the mani's that do not go out with the exhaust?

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.

 

[badman]

Re: help with omc stringer 400 water direction and pressure

ok. i pulled the drive. not too bad actually. no stuck bolts and oil where it should be.
Of course i expected to find some water in the oil as i will need a few new gaskets.
Even the impeller is fine.
All waterways are clear, if a little salty.

Left trunion cap is clear, right one is clear but where it goes into the IH is blocked or closed.
Left waterway / trunion cap passage goes to IH left port fine.
IH top port on right returns water to the exhaust waste area so looks to be a good way for water to leave.