Help with finding Sea water pump Part #
 

I'm trying to find a impeller kit for my sea water pump and all I'm finding is kits for the alpha drive. Do they use the same kits? I went to west marine and they were much help. The Merc manual did help much either because I couldn't tell exactly which kit I needed. Any part numbers for Merc or Sierra would be helpful.

The engines are 1985-1986 Mercruiser 300 Tempest 5.7L w/ Alpha 1 drives.

If my memory serves me right, isn't the impeller on the vertical shaft on the drive? You don't have a seawater pump on the motor do you?

Dave

If so, part number 46-96148 (A8, B8, Q8, or T8) for the last two. Any of those should work if the pump is on the lower, which it should be.

Dave

Yes there is a sea water pump that is belt driven. It is down low and connects directly from my thru hull fittings, to the sea strainers, then to the cooling tube on top of the engine.

Ok, different set up for an Alpha. Is your fuel pump intrigrated on the same housing? A picture would help.

Dave

Sea pump is below fuel pump which is located on the block. I'll what I can do to get a picture up. West marine sold me a sierra kit with number # 18-3217D on the package it states that it replaces part # Merc 46-96148a5.

The part they sold you is for the lower unit on your drive. Maybe you are running 2 pumps? I am not familiar with this set up.

I think you should post this over on the general tech question section. I don't think I am helping much.

Sorry,
Dave

Wow...sounds like a Bravo set up. I've never seen that set up for an Alpha.

Found an exploded view in the link below. Appears to be identical to the pully-driven Bravo setup.

http://www.marinepartsplus.com/catal...14#612268_jump

Atta boy bird. Good find! I'm sure that is the right one. What about the internal pump? Do you still need that one too?

Dave

Yup, thats the diagram for the sea water pump. I'll post the the serial number of the outdrive tomorrow morning. I was told they were alpha's but I have trouble decodeing the Merc serial number list.

Mike...you have something unique...you might have Bravo 1 drives retrofitted to that boat but I don't think so.. The Tempest option was extreemely rare...it was available as a MR (Alpha/MR) or with a TR (TR/TRS transmission and drive. I had a '86 272 LS that I special ordered with 320 EFI 5.7s that ran through Alpha 1 drives. The 320 EFI replaced the Tempest as Mercs "hottest" small block. To find a TR/TRS set up twin on a 233 Interceptor makes yours a very special boat indeed. Alpha drives weren't out yet in '79 and since the Tempest was only available in '85 & '86..my bet is that one of your previous owners took the Tempest set ups from a '85~'86 doner boat and put them in your Interceptor.

Take a pic of your drives and your bilge arrangement...this could be a history lesson...could it be that you have a TR or TRS drive set up? Are there transmissions immediately behind your engines? I have never seen one behind a small block but I think there were some produced.

It wouldn't be the first time someone took the pumps out of the alphas to run the engine-mounted pump. I think the alpha pumps don't support multiple/large coolers, heat exchangers, crossovers, high HP/speed, etc as well as the engine-mount variety.

Thanks for all your help. I'm learning ton of good info. I don't think they trs drives I don't see a tranny or the hydraulic lines to it. . Here are some identifiable features on them. A squareish top cap that measures about 4.25 inches across with 4 bolts. On the front side of the cap it kind of tapers down with a round-ish profile to it. The cap is flat with a hole in it, not a raised eyelet like the "R" drives. The rams are held on with washers and nuts. There is a oil vent hole the port side with a slotted plug.
So if the out drive raw water pump was removed and I just ran the engine driven pump how do the drives get cooled? Through the bell housing ports then out through the drive pick ups??

OK...I'll supply the pics...

Do your drives look like No. 1

http://i705.photobucket.com/albums/w...k49/alpha1.jpg


No. 2

http://i705.photobucket.com/albums/w...rink49/TRS.jpg

or No. 3

http://i705.photobucket.com/albums/w...ravo1drive.jpg

Haha. Drive identification for dummies. Its definitely no. 1 !

OK...we are all learning something here. This is the FIRST time I have had knowledge of a MR or Alpha Stern Drive set up using a secondary engine driven raw water pumping system instead of the one provided in the drive.

Very cool.

Where are the pick-ups in the hull?

So I was looking at the the piping this morning there is a large diameter (1.5-2in) coolant pipe that comes out of the top of the alpha gimbal ring on the inside of the transom and this goes to a thru-hull on the transom. So it looks like the alpha water pump is probably still intact and cools the drive only then pumps dumps out overboard.
Now the engine driven pump, goes like this. water pickups are about 1 foot forward from the engine pulley, the water then goes through sea strainers, then up to the pump. From there it goes up to the "cooling tube", then I don't know?? I see two more lines coming out of the "cooling tube" one goes to the water pump which is a filed with coolant, and the other goes up to a "T" near the thermostat housing which splits to each side of the engine block, also filled with coolant. So my question is, besides where the output of the cooling tube is, is this system going to work?

It should...is there a sea cock on every penetration thru the hull? Make sure there is...sounds like you need 4...2 for each side. I would love to see pics of all of this...do you have a camera?

Took a closer look this morning. The flow of the sea water comes in from the the sea cocks in to sea strainers, then the the sea water pump. From there it goes to the cooling tube then to elbows under the manifolds and out through the tail pipes. And I have two sea cocks, one for each thru hull fitting.

The flow from the alpha comes in through the sea water pump then in to the engine room through the top of the gimbals ( I think thats what the name is) then in to a hose that is piped in to the thru-full fitting located on the transom. So the water exits outs these fittings which is at the same height as the exhaust pipes.

Sprink thanks for all your help and your knowledge. I do need to hit you up for some pictures. And I would be more then happy to send some of my own. Do you have an email I can access you at?

Is this a closed loop cooling system? Is there anti freeze in your motors of fresh water?

Yes, it is a closed loop system.

So back to my original questions after this drive identification debacle.

-What kits do I need for both my alpha drive and the engine driven pump pictured here?

http://www.boats.net/parts/search/Me...%29/parts.html

I'm going to say if you order the kit for a 260 Alpha One that you will have the drive covered...I do believe all of the Alpha One and MR drives carry the same water pump impeller and replacement gasket kits for water pump service...probably the most common drive combination ever produced.

As for the Tempest raw water pump I would contact the vendor in your link at boats.net and ask them.

Hey sprink I want to run something by you.
So the engine and drive systems are cooler independtly on my boat. And the seawater is introduced in to exhaust system at the bottom of the risers. Would a better way to go be to route the seawater to the transom fittings where the alpha dumps its water overboard? I'd like to run the boat in salt water and without that running through the risers it would extend their life a bit huh? Forsee any problems other then louder exhaust?

I believe what you are talking about is what is known as "Dry Exhaust"...don't try it...the risers and manifolds will run too hot and set the bilge on fire!!:eek:

I sure would see a few pics of this. Where are the heat exchangers located?