How to install and test an impeller on a Ford 351/Indmar?

pcm2a · Soul Rider Joined: 14 Jun 2004 Posts: 318 City: LaVergne

Hey all! I have a 1991 American Skier that has a Ford 351/Indmar engine, carbureted. Took the impeller out last winter easily and even drew a diagram to make sure I install the impeller fins the right way.

The inside of the impeller is metal and is not a square that can only be inserted one way, but it is a many pointed star. I do not see any identifying marks signifying that it has to be inserted a certain way. By that I mean that some impellers have a groove or something so they can only be inserted one certain way. I install the impeller in and I can see all the way to the back of the housing to make sure that it is all the way in. However the impeller seems to stick out of the housing about a millimeter.

I put the lid on the housing anyways, fire up the boat, but I do not see any water coming out of the exhuast, my leaky mufflers, or even in my water separator.

The next thing I try is firing up the boat with the hose coming out of the impeller off, and there is no water.

Finally, I start the boat with the front off the impeller and I can see it spinning just fine.

Questions:
1. With the front off of the impeller housing should it still be bringing water up from the plunger/hose? If so then I must have a problem somewhere between the hull and the impeller.

2. If the housing must be sealed, could the front of the housing be pushing on the impeller so hard that it is not turning. That seems unlikely, since it seems like it would just strip out the impeller.

Any other ideas or things I can test?

From the hull is a hose. This hose goes straight up into the water separator. I used a diagram to make sure I put the separator on right, and it has a big arrow on it. From the separator the hose goes down and along the side of the engine ending up in the impeller.

Thanks!

DRAGON88 · Posted: Apr 01, 2009 2:57 pm Post subject:

pcm2a, it doesn't matter what directions the fins are pointed, the impeller will orient them.

It seems to me that you don't have the impeller properly seated, and yes, that would cause problems. Also how new is this impeller, I'd probably put a new one in if it's been more than a few seasons. (I replace every two years.) If the housing is not sealing all the way then the impeller is not going to be doing its job.

Although with a hose, I would think that there should be enough pressure just from the hose to be getting water to the impeller housing its self. Have you checked to make sure the thru hull shutoff valve, is not closed?

Also it seems to help to use lots of soapy water to get impellers in and out, or at least that's my technique...

pcm2a · Soul Rider Joined: 14 Jun 2004 Posts: 318 City: LaVergne

Impeller was purchased last year and looks to be beautiful and plyable still. It is a long way from that impeller to the hull considering it goes through about 4 feet of hose to the water separator and then another 2-3 feet of hose to the hull. I have not see any hull shutoff, so if there is one I surely didn't close it.

I'm about to go test putting the hose going into the impeller into a bucket of water and see what happens.

pcm2a · Soul Rider Joined: 14 Jun 2004 Posts: 318 City: LaVergne

Success!

I unhooked the hose coming out of the water separator and stuck it into a bucket of water. The impeller had no problem sucking the water up. So now I knew that the problem had to be the hose going to the hull or the water separator.

The next thing I tried was taking the water separator inside and filling it up at the sink. Reinstalled it and presto, everything running great. I guess the impeller couldn't fill up the water separator, but once filled it could create the required suction?