454 with alpha?
 

I know many of you have been over this a few times a 454 and alpha don`t mix well but I have not had any problems. I guess that means I baby her. I have a question about the cooling,the alpha water pump is in the drive, that`s fine when your up on plane the temps are cool 150*. If I have to go thru a long idle zone the temp will rise to 180-200* once out of idle zone temp falls like a rock right back to normal. I have checked the impeller thats fine and new temp sender.
What I would like to do is add a raw water pump and plumb it to the existing water line coming out of the drive at the transom. My theory is that the raw water pump will suck the water right from the drive like it would from a bravo, and still keep the drive cool.
Also is 200* for a short time that bad for a BBC.

Thanks for any input good or bad

mark

can i sell you a bravo 1 with a shiny brand new skeg guard :)

pump
 

i put a pump on my eng. and put a tru hull sea water pick up i left the pump in the drive to cool it. it worked great

good question i would like to know also.

I would suggest that your proposed new raw water pump will have more than a bit of a problem trying to suck water through your current Alpha impeller / pump. I kind of doubt you'll gain much. If your OEM pump is working properly, you shouldn't be over heating anyway.

Thanks for the replies guys, I am not apposed too putting a water pick up on just something I was considering. At idle speed and wake zone that pump just can`t keep up. Hoping to here from some alpha guys if they have any problems like this.

Should I go with a transom pick up or a thru hull.

My Alphas don't do that. I'd be more inclined to think you have a problem elsewhere.

I would put another impeller in it. When up on plane water is forced into the drive. I had an alpha and it did the same thing

Merc used to make a belt driven sea pump kit for big block Alpha's. Back in the day we would retain the Alpha pump but divert to a dump directly on top of the drive for cooling. Solved all problems.

If your impeller is good, then you have issues elsewhere.

Check for debris in your oil cooler, and check the spring loaded backpressure valves at the water neck.

AND make sure you have a marine thermostat, not a car one (marine ones have an air bleed hole, which you can add to a car one). Without an air bleed hole, you can end up with too much air around the thermostat, which keeps the bimetal from heating up and opening it.

Check the hose coming though the transom assy. It might be damaged. If adding a raw water pump, do as others suggested. Use a transom pickup for the rwp, and let the impeller cool the drive. You can let the water from the drive exit on top of the drive for added cooling.

I agree. I don't have that problem either. I'm running a 454 with alpha and mines been holding up just fine. its all about the nut behind the throttles. If i were to venture a guess, I'd probably suspect the thermostat. I actually run without one and mine runs a consistent 140. i did have a temp gauge surging issue while i was running a tstat. removing it fixed it. keep in mind though, if your water pump is on its way out, its just going to be a band-aid and it will leave you stranded in the not so distant future. alpha water pumps are very cheap. get a new water pump kit, check your inlet lines for any debrit, and check/replace your stat. all in all, less than 100 bux in parts, and a good piece of mind that your boat won't leave you stranded.

Thanks for all your responses, the boat is all winterized so most of this will wait till early spring.

Honda I was not sure about pulling the thermostat I may try that in the spring. I have been making a list of things that I was going to need for the raw water pump and all and it`s not cheap even doing it myself.

Thanks

mark

merc had issues with larger engines and alphas running warm, they changed the inside of the drive and went to a engine mounted bravo style water pump to cure the issue, if you do the engine pump use a thru hull or transom pick up....oh since you have had good luck with your alpha...maybe pick up a lottery ticket on the way home ?? only kidding

Along This Thread...
I'm Going To Drop My '01 7.4 Mpi Ito My 24' To Get Some Run Time On It While Waiting For My 28' To Be Ready.
It Has A Bravo I Coupler But I'm Hooking Up To An Alpha Gen Ii.
Will The Bravo Coupler Work Or Do I Need To Swap It?

You will have to swap it. Completely different. Alpha coupler bolts on by the flywheel to crank bolts. Here's what they look like.
http://www.sterndrive.info/alpha-one...i/coupler.html

The bravo coupler will work fine, I use them on all of my small block engines. The late model alphas use the same coupler anyway. All of the splines are the same.
Easier to install and stronger then the little crank mounted alpha units.
You must use a bravo or late model bellhousing which has the bigger hole to clear the coupler..

Has this thing ever ate an impeller? Maybe blockages in the system? Have you ever backflushed it? AND on my last alpha 350/260 combo I replaced what I considered a damn near new looking impeller twice and it fixed the problem.

I had problems with the Merc impellers lasting and the first sign was higher temps at idle and lower speed. Switched to the Sierra pump kit (needed a kit on a Sunday) and never had a problem again.

you don't really need a list of things you need to replace it. all you need is the whole water pump kit and an outdrive gasket kit. the gasket kit is about 12 bux and the water pump kit including the housing can be got on ebay for less than 50 bucks. make sure if you buy on ebay, you buy a decent brand like quicksilver or sierra as mercruiser parts are outrageously expensive for no reason. sierra and quicksilver makes good parts, and i have used them with no problem for multiple seasons in my boat.

My previous experience with Alphas I always ran cooler at idle and just slightly hotter at high speed RPM. It sounds, to me, like you don't have enough flow at idle. When you last replaced your impeller, did you just replace the impeller itself or did you use the Merc "kit" which includes the plastic housings? Also I would suggest a new water pump (on the engine)

3 things I have found in my travels, 1 already discussed is thermostat & debris from previous impeller failure. 2 I found this a few times the impeller not bonding to the shaft sleeve, (shaft turns normally but impeller slipping on sleeve). 3 Exhaust risers plugged up with rust not allowing water to exit properly,just a couple of ideas. Randy

the stainless impellar housing could be scarred up as well