OMC 400 Stringer New Pump Not Pumping

[flockshot]

New impeller pump not pumping water in 83 400 Stringer.
I started engine with hose to thurmistat housing disconnected and no water pumping with muffs or with outdrive submerged in a large tote.
Impeller vaines were installed in housing by turning counter clockwise while working vaines into housing.
New seals and permatex in the right places (I think). I used OMC sealers and lubes as described in the books.
Hooked garden hose to 'flushing adaptor' on starboard pivot plate and got some water running out of water intake so there is a open passage from the intermediate housing to the water intake.
Any ideas would be appreciated.

 

[full stringer]

Re: OMC 400 Stringer New Pump Not Pumping

try reversal of that process maybe a blockage and you can blow it out. do you have a power steering cooler because those can become clogged as well anyway try to backflush see what happens and good luck

 

[full stringer]

Re: OMC 400 Stringer New Pump Not Pumping

did you remember to install the key way on the impeller shaft? just askin because in a rush to get er done we all can make errors

 

[flockshot]

Re: OMC 400 Stringer New Pump Not Pumping

I will try the backflush idea.
Yes I did put in the key for the impeller, but thanks for asking. It could easily have been something like that.

 

[zbnutcase]

Re: OMC 400 Stringer New Pump Not Pumping

Pump housing in upside down?

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

there was a batch of bad impellers some years ago...GLM maybe?
where the rubber was spinning on the brass insert....

all I can think of at the moment.

Is this in the lake? or on muffs?

if a barrel, remember the whole entire drive is submerged in the lake.

 

[flockshot]

Re: OMC 400 Stringer New Pump Not Pumping

Pump housing is installed with the impeller cover facing the lower unit of the outdrive. Installed by taking the shaft and putting on the impeller cover (pump side to the impeller, inserted the key, put on the impeller and twisted impeller into housing using a counter clockwise motion. Used Permatex 2 on outside rim of impeller cover plate (both sides) and on bolt threads and bolt head/washers.

I used muffs and when that failed to get water to the intermediate housing, I filled a large tote with water making sure that all water intake holes were covered with water.

Since the muffs didn't get water to the intermediate housing (some water pressure there so I thought it should) I hooked the garden hose to the 'flushing adaptor' on the starboard pivot cover and when I turned on the water I did get water out of the lower water intake holes so there is a open passage through the upper unit to the water pump.

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

doubt this is the issue, because the muffs should have been fine, but for future reference:

all water intake holes were covered with water.
.

that's not even close to being deep enough to prime

the entire impeller housing has to be completely below the water line of the tub

which is impossible without tilting the drive and the drive shouldn't be run tilted

i.e. tub + stringer = no good

this is the proper depth for priming:

 

[flockshot]

Re: OMC 400 Stringer New Pump Not Pumping

Thank you for that Howard. I won't waste my time with a tub an more.

I was concerned that I could put it too much pressure on the upper case seals with the muffs so I ran the water at a pressure that would make a stream shoot straight up about 2-3 inches out of the hose.

Do you think that I should use more pressure? Perhaps I could take the hose fitting cover off the starboard pivot cover flushing adaptor (as a pressure relief measure) and run the hose at a high enough pressure to get some water out of that hose fitting and then see if it pumps.

 

[HorizonblueDK]

Re: OMC 400 Stringer New Pump Not Pumping

A few years ago I changed impeller and housing on a pair of OMC stringers on a friends boat (electric shift), GLM parts.

I noticed a small notch on the new impellerhousings, that wasn't on the old ones.

Anyway I installed the whole thing and started the engines. One was pumping and the other didn't.

Took the non-pumping drive apart, checked everything, ok, assembled again. But it refused to pump.

Took it apart again and installed the old housing with new impeller. Started the engine and guess what; it pumped!

I'm 100% sure that both drives were assembled the same way in the beginning.

Decided to take the other drive apart and install the old impellerhousing, since I was a little nervous about the notch. Could air be drawn in that way and disturb the pump cycle?

Anyway, the boat didn't sail for many hours, before the annoying pump stopped pumping again, and the engine ran hot.

My friend asked for advise, and we decided to scrap the pumps in the drives and install crank mounted Johnson pumps instead, with through hull intake.

That works great, and the impeller is much easier to change.

Since the engines are 165 hp inline 6, I had to fabricate new front motor mounts, to accomodate the protruding pump.

I newer found out what was wrong with the non pumping drive, but I suspect a leak, where air can be drawn in.

This should not be at problem, when the boat is in the water, but when you get on plane, it will start to take in air.

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

I was concerned that I could put it too much pressure on the upper case seals

nah. open the hose full.

it can't build much pressure- the water is free to flow up and over the risers and pour out the exhaust

unless your risers are plugged
__________________

dump it in the lake

remove the hose to the thermostat and start it up- should shoot like a garden hose

better yet, install one of these $4 flushing tees so you can check the pump in 20 seconds every outing... peace of mind is the name of the game

 

[flockshot]

Re: OMC 400 Stringer New Pump Not Pumping

You make two really good points.

1) The old cast iron pump housing does not have 3 'notches' that the new one does. These notches are where plastic plugs go so that the next time the housing needs to be removed, screws can be put into these plastic inserts and a 'puller' can be used. Is there a air leak there?????

2) I will hook up the hose in the morning and find out it this thing will pump or not. If it does I will watch it closely, and put in the tee you refer to. if not the old cast iron housing is going back in. A rubber impeller is not going to wear out cast iron.

I will post the results.

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

cast iron under water?

They're all aluminum that I have seen, but OMC does make some sort of heavy duty kit for the stringer drive. ($)

0983219 HEAVY DUTY WATER PUMP & IMPELLER HOUSING KIT 1 $478.74

I have put quite a few GLM kits in and never had an issue with the housing they have in the kit.

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

btw, grease the heck out of the swivel bearing for good water pumping on a stringer

 

[flockshot]

Re: OMC 400 Stringer New Pump Not Pumping

PROBLEM SOLVED

Turned out to be a I.O. problem (idiot operator). I simply wasn't using enough water pressure on the muffs to prime the pump, and the tub wasn't deep enough to prime it either. Moral of the story is, if you want to check your water pump, put the boat in the lake.

I now see the detail picture of the 'notch' in the housing and my new housing did not have that notch. The housing I took out is not iron as I stated. It was a machined cast part that was heavy for it's mass and I assumed it was iron and set it aside and never looked at it again till today. It looks like aluminum but is much too heavy to be just aluminum. Part number cast into the housing is 909649. If I change the impeller again it will go back in the boat.

I will also install the 'T' in the raw water hose as shown above. It will come in handy for checking the flow and winterizing the engine. Like you say, it is about piece of mind.

Without the help of you folks I would have torn the whole thing apart again and probably come out of it with the same result. Thanks so much for taking your time to help me figure this out. It really felt good to see that water pumping out. Now I don't have to waste any more of our precious Michigan summer time.

 

[Howard Sterndrive]

Re: OMC 400 Stringer New Pump Not Pumping

29 0983298 IMPELLER HOUSING
29 0909649 IMPELLER HOUSING, Heavy duty

yep, that's the heavy duty housing.. neat

hang onto that part for sure. It's the one in the $400+ kit. must be some sort of cast stainless stuff

 

[full stringer]

Re: OMC 400 Stringer New Pump Not Pumping

hey just to let you know my book says to install the impeller into the housing clockwise not counter clockwise oops!!!!

 

[full stringer]

Re: OMC 400 Stringer New Pump Not Pumping

im sorry did you mean you turned the housing counter clockwise while you installed the impeller or the impeller counter clockwise while pushing it into the housing