Just tore down my first Alpha for Water Pump - What I found..

[dg512055]

I just pulled the drive off the bell housing and separated the upper from the lower. I found the water pump only had one gasket - between the lower gear case and the wear plate. No gasket above the wear plate. I will be replacing with correct gaskets. Also, I looked into the Y-pipe and see both water shutters sitting there. I fished them out with a gripper tool. (I am unlucky enough to have the batwings). I am wondering if there is any harm in leaving the shutters out. I ran all summer like this with no problems. I am also replacing the original thermostat, which was stuck in a slightly open position when I removed it.

 

[DockedPay]

Re: Just tore down my first Alpha for Water Pump - What I found..

I've been told that running without the shudders risks water getting back up into the engine (which is bad) the following ways:
1 - stopping quickly and the wake forces water back in (shutters stop this)
2 - while reversing quickly the same can happen
3 - when launching and backing the boat into the water on the trailer can force water back up the Y pipe

Shutters there to help stop water in these situations. They aren't that hard or expensive to change either.

 

[Friscoboater]

Re: Just tore down my first Alpha for Water Pump - What I found..

How in the world do you change them without taking the engine out?

 

[Chris1956]

Re: Just tore down my first Alpha for Water Pump - What I found..

I had the two piece manifolds on my 4.3LX, and the shutters fell out years ago. the parts guy (and owner) at the mocal MerCruiser shop advised that it wasn't necessary to replace them.

I never did and never had an once of trouble. I would think you would be OK, provided the manifolds are high enough above the waterline to keep out any waves.

 

[ltklein]

Re: Just tore down my first Alpha for Water Pump - What I found..

From the Armchair Mechanic..

Interesting that my manual sez the inline engines' shutters can be serviced from the back, but the V8 must have the engine removed because they're in the exhaust separator.

It doesn't mention the 4.3, but since it is a "V" engine, I'm guessing it similar to the V8. Experts can confirm.

Roger

 

[haulnazz15]

Re: Just tore down my first Alpha for Water Pump - What I found..

The stuck thermostat may have caused the engine to take longer to heat up when cold, but other than some poor fuel mileage it doesn't matter much. The water shutters are cheap and should be replaced. You can run without them and many do, but it's worth the piece of mind if you're already messing with it. Mine were missing as well, but since I was already pulling the engine, it was just easy to do. Suck some water into the engine just once and you'll be pulling the engine anyway with much more expensive parts to replace.

 

[WizeOne]

Re: Just tore down my first Alpha for Water Pump - What I found..

This has been discussed before. The most likely scenario to get water back up the exhuaust path is when using an exhaust tube instead of the bellows, when the boat is beached, bowfirst, stern downward and outdrive up. Waves can enter the unprotected tube.

With the outdrive in the run position, it is unlikely that any water will get all the way back up to the risors, even when backing up.

Also, at some point, Merc started putting the flappers at the top of the Y pipe, not at the bottom. I'm not sure what year or model that was but if it is the case then you just have to pull the risors and sleeves to get to them.

 

[Aviator5]

Re: Just tore down my first Alpha for Water Pump - What I found..

I've done it on my V-6 without pulling the risers. Just pull off the rubber sleeves.

 

[WizeOne]

Re: Just tore down my first Alpha for Water Pump - What I found..

I've done it on my V-6 without pulling the risers. Just pull off the rubber sleeves.

I don't doubt you but I'd like to see that! My only reference, however, are the risors and sleeves on an older Merc 888. I had the risors off recently to replace cracked sleeves. I don't think there would have been any way to replace them without pulling the risors.

Maybe you have center risors with longer sleeves?

 

[DockedPay]

Re: Just tore down my first Alpha for Water Pump - What I found..

Ya, these shutter or flappers or whatever that I'm thinking of are located in the rubber boot where the riser elbow meets the downward run of the Y pipe at the back of the engine. In a merc V8 there will be one on each side obviously. You don't have to take out the engine at all, but like one of the previous posts indicated (and what I did) was undo the riser to remove the rubber boot. It can be done without cracking loose the riser but good luck with that. ALSO! if gonna do the job, I did mine while the boat was still in the water but if you do MAKE SURE that entire boot is above the water line! If not when you separate it water will POUR in. If your not sure I'd pull it out of the water to do the job. A set of shutters cost me about a $100 bucks and the job took me about 2 hours tops.

Also as previously mentioned, some guys just run without them but the risks still exist re my first post.

 

[riverratjody]

Re: Just tore down my first Alpha for Water Pump - What I found..

I have the batwings also on my 98 4.3L, but I'll replace them before the winter is over. One has rusted through. I have assembled the used conversion parts from ebay but will probably buy the new maniflods and elbow/risers. Think I saved myself about $400. I also replaced the shutters and it was pretty easy. About $35 each? Should be able to slide the bellow up onto the manifold enough to reach in the Y tube and place the shutter in place. Only need an inch or 2.

 

[rebars1]

Re: Just tore down my first Alpha for Water Pump - What I found..

WizeOne: In my 888, the shutters are way down where the Y-pipes connect to the transom. You need to pull the engine to replace them.