1993 Mercruiser 5.0 LX Not Pumping Water

Are you sure the drive is turning?
Does the prop spin in forward and reverse when idling?
If the upper gears or the engine coupler are shot the drive does not turn, and hence no water pumping.

Rod

Yep, I put it in gear to make sure and yeah it spins the prop. I'm sure it has to be turning then, right?

Mike Kaldy said:

Yep, I put it in gear to make sure and yeah it spins the prop. I'm sure it has to be turning then, right?

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Right.
Are you sure you have enough water feeding the muffs?
You should turn the hose on full blast.
There should be water escaping aound the muffs, even when you start the engine. You can't have too much water.

Are you sure the hose between the drive and the transom assembly is not kinked?
How about the hose from the transom assembly to the T'stat housing?

If the water pump impeller fragmented at some earlier date there may be chunks lodged in the intake piping somewhere.
Is the water pump outlet properly mated to the coupler and water pipe in the drive?

Try removing the intake hose at the T'stat housing and let it pump into a bucket for 10-15 seconds. It should fill the bucket quickly.
If not, then work backwards.
You should probably have replaced the impeller anyways, for what they cost and the fact you already had it apart.

Rod

If water does not flow at all then did you put the key on the shaft w/the new impeller? If yes, then try what Rod stated. Still not getting water to T'stat then remove the hose inside the transom and check for a blockage at that connection. Back flush it from there and see what comes out.

Consider this with the water pressure from the hose even if the water pump was not spinning you would get water to the motor.

Hence the reason you are being told there is ether a blockage outside the transom, or the hose inside the transom is kinked.

The water hose that comes in from the transom might go to a heat exchanger first, then that is where you pull off the hose and start the motor and see if you have water to that point.

But be aware on a hose the pressure of the hose might push water that far.

First try it then latter you can submerge the drive to see if the pump will draw water.

Say you don;t get water to that point you can back flush with water to see if you can clear the drive of obstruction, or put regulated compressed air to it.

like the others have said, sounds likea piece of old impeller broke off and is clogging something, running a new impeller with out water will ruin it pretty quick also.

I did run water through the hose that goes from the outdrive to the t-stat housing and water flows right out the intake holes. We put water to the copper tube in the upper outdrive when we took the lower off and it pumped water right up to the engine. I gues replacing the impeller it is...

Mike;
Can you use a quick procedure on changing the impeller? Or do you have your own manual?

Rod

Mike Kaldy said:

We put water to the copper tube in the upper outdrive when we took the lower off and it pumped water right up to the engine. I gues replacing the impeller it is...

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I am not sure how you managed to do this, since the impeller is in the lower gearcase which you removed? Do you mean that you were able to force water up to the engine using garden hose pressure?
Another thing; what kind of muffs are you using?
The only kind that works any good is the springy V shaped type with the suction cups on either side. The strap-on type are junk as they let air in instead of water.

Rod

Yeah I did have the spring type v muffs for the water. And yeah, I did try pushing water through the hoses to the engine with a host while the lower unit was off. I just pulled the inlet hose off the t-stat housing and it came right through. Anyway, I ended up pulling the outdrive apart again and checking the impeller thoroughly, which was still fine, so I put it back together and headed to the launch ramp to completely submerge the drive unit. I pulled the hose off the engine for a couple seconds when starting to check for water flow, and sure enough it filled my bucket right up. It just needed to be completely submerged for some reason. I clamped the hose back on and let it warm up and everything seemed fine. Went home, changed the oil, filter, fuel filter, drive lube, and am ready to head out to the lake tomorrow to try it out for the 1st time

Good luck! Let us know how you make out.

Rod

Well it went pretty well. I made sure to grease all the grease fittings before going out too. First though was I was surprised at how maneuverable the boat was, even compared to my 1974 Sea Ray SRV 190. I havent had much experience with Mercs, so at first the clunking into gear was a little alarming, but from what I hear thats pretty normal for this type of drive as compared to an OMC like the Sea Ray. It just seemed like it grinded when moving it very slowly from N to Forward, but it didn't do anything really if I just put it in firmly.

Once I got on it a little, it started bucking a little like it wanted to quit, so I let it go down a little in RPMs and tried again and everything seemed to go alright for the most part. It was a little picky at idle though, like it wanted to die sometimes. I think it needs adjusted cause it was at 500 or so rpms, and I'm sure it could probably use a cleaning/rebuild on the carb. And I'm just going to put new plugs/wires/ maybe a coil on it tomorrow for good measure. It maxed out around 39 on the speedo on a short sprint just to see what it had. I didn't think it was too bad for a boat of this size with a 305.

Just figured I'd let you know and see if anything sounded wrong.

On another note, is there a way to adjust the steering to tighten it up a little? It seems just a little bit loose, yet not too bad.

Do the shift into forward or reverse quite quickly with Alpha drives. Otherwise they do make a ratcheting noise, which is not doing them any good.
You may have a loose steering arm or steering shaft.
With the boat on the trailer move the drive by hand left and right.
You should have little to no side to side play.
If you have noticealbe play, you may need to tighten the steering shaft to lever bolts, or shaft to gimbal bolts.
If they are too far gone, you may need to replace them.
There are several other topics about this issue on the board.

Rod

Alright, thanks for all the help. Just got the repair manual ordered tonight too, so I should be good for a while. Only a little bit of the boating season left this year for me anyway here in OH.