On my last boat w/a B3 drive I would run it on muffs no problem. The new boat w/ Alpha drive does not seem to draw water.I get no water exhausting through the transom assembly as with the Bravo. I want to warm it to change oil but don't understand whats up. Want to avoid creating problems. Thanks for any help.

I believe, my Alpha exhausts throught the prop hub....Thru Hub exhaust.

I assume there are Thru Hub and/or Transom Exhaust setups in the world.

Maybe the experts will chime in soon on your particular type....

I'd say you have a bad impeller in the pump in the lower unit. Exhaust works the same on Bravos and Alphas, it's thru hub, with exhaust reliefs at the transom.

I always need to bump the throttle to get the flow going plentifully before backing it off to idle. I'd say about 1100rpm should do the trick. The water should be flowing like crazy if your impeller isn't shot.

Its a 5.0 Alpha w/14 hrs on it.Runs great, no overheat on the river.Just expected it to act like the Bravo on muffs.I get the Exhaust rumblings but no water pouring out.I have a 1" ID idustrial hose and high pressure /volumn water supply. Ran it twice for about 30 sec and stopped until I understand sustem better.Different enough from the Cobra and B3 that I need to ask.

When I put the new impellers in the Skip's Alpha's this spring and test fired them, I turned on the water (not full blast either), walked up front and blipped the starter, and by the time I got back to the transom I had exhaust water. Of course the 4-bangers don't hold as much water. But the common issue is, the seawater pumps are positive-displacement pumps, which means they will also pump air, and suck water like gangbusters. If you have to rev your engine to get water, or are getting no water, something isn't right...

I have a 2000 5.7L w/ an Alpha and get plenty of water out the exhaust on muffs at idle. I never put the hose on full blast, just medium flow pressure. I've also never had to goose it to prime it and get water to flow.

Since it only has 14 hours on it and does not overheat in the river I would suspect something w/ the muff hook-up. Are you sure the muff cups are placed properly over the intake openings on the drive? I would suspect a thin walled collapsing hose wall restricting water flow but your "industrial" description seems to rule that out. I've heard the hose walls can collapse from suction if you rev too high.

Double check the cup alignment is my only advice. Is there an online photo of the muff set you are using? Some have a pin that goes through the vent holes to hold the muffs in place. I have a more basic set and they work fine.



I don't have that type, just a basic set like below. I make triple sure its aligned properly over the holes. I'm sure you've checked this, but that's all I've got! Maybe post a pic of your setup?

I'm trying to think how long the delay is if any, but just don't remember if I ever had any even when the block had been drained. I could see maybe a bit if the block was drained first, but just don't recall having to wait around. The impeller is right there in the outdrive so it should be picking up and pushing through water pretty quick.

One other thing to notice. Is the volume of water pouring out around the muffs the same before and after starting?...even if you don't see it flowing out from the transom area?...or is the spillout from around the muff seals about the same?

My muffs are of the second picture design but water flows from both sides and the muffs are rectangular in shape to better cover the inlet. I will try again tonite, how long can I run it before impeller problems occure?

You do not want to run more than a few seconds without water coming out. My alpha spits some out the prop hub and quite a bit out the exhaust relief on the left side of the transom assembly.

Make sure the muffs are fairly tight around the inlets. You may have too much water pressure which may be pushing the muffs away and making a poor seal.

At first, try a medium-low flow of about 2 gallons a minute, so the water will just "gently" spray away from the muff seal edges while the engine is off. Assuming the pump is good, the spray WILL noticeably reduce when you start the engine. At about 2000 rpm, the overspray will be nearly gone as the pump will be sucking up all your giving it...

How long can I run(test)it before impeller is effected, It does not draw like the B3 did.

I run impellers dry for 4 or 5 seconds without harm all the time. I figure I can get away with this because there's residual water which is sufficient for a quick 'test fire'.

If you're feeding water thru the muffs and it's apparent the water isn't being pumped up, then 'theory' says your impeller is already affected...

Just an aside, if there's one thing I've learned over my many years, it's that, like s***, "coincidence happens". This is (imo ) a Murphy's law that says it doesn't matter if something worked fine one minute, it can completely not work the next minute for no other reason than 'coincidence'. This will drive a do-it-yourselfer nuts. One time I changed jets in a carb, when I was done, the engine started running like total crap. I thought I'd done something wrong with the carb. So I put it back the way it was. Still ran like crap..?? Turned out I needed spark plugs and wires. Stupid thing ran perfect until I took the carb apart.

In your case, your boat seemed to be fine, and wasn't overheating last time you drove it, but now you can't get water to pump. It may be an anomaly, or maybe when you started it to test it, your impeller lost some blades and refuses to pump now.

weather it's my bravo III, the Alpha or the Gen I always had water flowing from gimbal outlet and through exhaust/prop hub before engine ever starts... If it's not coming out there is a problem..

Isn't there a hose in the engine compartment (waterpump?)that you can unhook to see how the water is flowing?