My Daytona has a cam driven Magnaflow water pump.
It cools the engine OK ( too cold ) but won't get primed and start pumping until the boat gets up on plane and some water is forced into the pickup on the bottom of the hull.
I put a 1/2 " brass "swing" type check valve right on the hull pickup and filled the line with water and it still didn't want to get primed until the boat gets up on plane.
There has to be a better way.
The impeller looks to be in good condition.
???
If they're in good shape, they should self-prime, even with the boat sitting still in neutral.
If they've been sitting a long time, the vanes on the impeller can become distorted and fail to make good contact with the outside of the pump housing, and they won't prime. And an old impeller can become inflexible enough to follow the shape of the housing. Try a new impeller. You could try mine off my spare motor, but it's been sitting a long time too.
A little Marvel takes care of that!..
Pull the cover and check the impeller. Buy 2 extras from Rex.
I had one go and ended up digging impeller out of my block.
Hobby
My Daytona has a cam driven Magnaflow water pump.
It cools the engine OK ( too cold ) but won't get primed and start pumping until the boat gets up on plane and some water is forced into the pickup on the bottom of the hull.
I put a 1/2 " brass "swing" type check valve right on the hull pickup and filled the line with water and it still didn't want to get primed until the boat gets up on plane.
There has to be a better way.
The impeller looks to be in good condition.
???
I hav'nt had a proplem with priming, but my motor did run to cold , I wound up having to run a waste gate valve to cut down on water, I was able to regulate temp. with valve.
Thanks for the responses.
I'll take out the impeller and look at it again.
While its taking it's time to prime up, the pump housing gets extremely hot.
I'm sure that causes the impeller to progressively deteriorate causing it to take longer to prime......etc.
Never run them dry you can kill an impellor in 30 seconds, after it sits and it's dry I always pour some Marvel in the inlet(WD works too), that primes it and lubricates it till the water reaches the pump!..
:argue: Sounds to me like its sucking air between the pump and pick up. I have used these pumps for years and have never had a priming problem. I know I have had as much as 6 feet of hose on the trailer and sucked a five galon bucket dry befor I could turn the hose on...Even when crap from a old impeller had blocked the outlet dumps they pulled water, they just pushed out alot of steam. Check your fittings for cracks and look over the hose. You might put a hose to the pump and try the bucket trick. Make sure the pump housing is not cracked or the o-ring is bad. One has to fix your problem. Hope this helps
Mike
Never run them dry you can kill an impellor in 30 seconds, after it sits and it's dry I always pour some Marvel in the inlet(WD works too), that primes it and lubricates it till the water reaches the pump!..
Well mines been kilt then.
It looked like new when I first got this and the pump housing looks excellent.
I'm sure there are no air leaks, a couple new impellers looks like the best plan.
With the check valve I put in the line it will hold water in there and lessen the time it takes to prime in the future after I install a new impeller.
How much pressure is needed to open that check valve? Perhaps the extra resistance of having to swing the check valve is enough to keep the pump from priming. That might explain why you have to force feed it by getting on plane to fill the line past the check valve. I'd pull the check valve, put the plumbing back to how it was, and replace the impeller. If it works fine, and you want to test your check valve theory, it would be easily done from a then "known" state.
Chris
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