772 Hamilton

[safesheet]

I have recently purchased an 87' Whitewater sled. 772 Hamilton with a Ford 302. Picked up the boat in Medford, OR and it's now in SW Colorado. I found that a jet looses appx. 3% HP for every 1000' feet above sea level, I'm at 7000'. The first time out the boat ran ok but I felt that it could give more. The second time out I picked up some weeds and pulled out what I could then hobbled back to the marina. Last trip out the boat wouldn't go more than 5mph, good throttle response and the engine sounds great but only hit 2800-2900 rpms at 5 mph. I suspect that the problem is in the jet pump but I cannot find a overhaul manual any place. Not sure where to start. Unfortunatly the only 2 boat repair shops in town are not fimilar with jet drives. Any help would be greatly appreciated, especially a tear down manual, I am willing to purchase. Thanks.

[RivrLivn]

I would suggest you post the question on
http://www.riverjetmagazine.com
That site has a lot of knowledgeable people on those kinds of boats.

[safesheet]

Thank you.

[Pericles]

http://www.hamiltonjet.com/

Pericles

[safesheet]

Thanks for your reply, I have not been able to find a diagram or overhaul manual through Hamilton. I emailed them a couple of days ago to see if they could help me and have not recieved a reply thus far. I did find Seloc's Jet Overhaul manual but cannot find a copy available anywhere either.

[marshmat]

I've been in contact with the folks at HamiltonJet now and then, not on a very regular basis... they take a few days to figure out what to do with your questions, but seem to be very thorough with their customer service once they do.
I can think of a couple of things that could be involved with your problem. One possibility is that when you sucked up your weeds, you either didn't manage to get all of them out, or you sucked up something else with them that got into the shaft bearings. The implication being that there is a lot of extra friction in there, restricting the unit's ability to spin up. You may have also picked up something that damaged an impeller blade or an outlet vane.
I've never torn down one of these units and so can't help you on that front.

[safesheet]

Matt,
Thanks for your reply. I hate to pull that pump apart without some guidance on getting it back together and identifying a faulty part with a part number. Still looking.
Tim

[redtech]

safesheet, just 2 cents more and having worked with jets, take a look at the engine if going for medford to 7000ft you are going to need to leen the carb out a little, may have to retard timing a touch and if your boat has 1982 ignition on it check your points
jets are pretty simple in river sleds and that 772 has been remade by k.e.m., jetpack, and marine power

[safesheet]

I wasn't aware that there are other manufacturers for the 770 series. I will look into the companies that you shared and post my findings, thanks a bunch.

[redtech]

these are not other manufactures for the hamilton
these are manufactures that have copied hamilton

[safesheet]

I understand. Hamlton had a patent for the pump wich is good for 20 years. After the patent was expired(in the last few years) the design is on the open market and others have now made copies. Thanks for the clarification.

[EStaggs]

Get her on the trailer.

Pull the intake grate off the bottom, and the discharge nozzle off the tail. These two pieces can be had apart easily and don't require a manual.

Get the brightest halogen light you can get your hands on, and shoot it in.

I have had similar losses due to a combination of factors happening simultaneously. A dull leading edge on my impeller caused considerable aeration, with massive losses. On a recent crabbing trip, this combined with a 6" long blade of seagrass which wound against the shaft caused me to only have about 5-7mph progress with a perfectly tuned engine.

So often its either debris in the pump, or debris that has worn or destroyed the leading edge of the impeller. On these units, once the aeration begins on that blade, you will never regain any semblance of waterflow in the pump until you iron it out. With outboards, its as simple as tuning the edge back sharp, but inboards are a little more challenging. The leading edge should be abour 1/32" to 1/16" thick, with smooth surfaces flowing into the blade. Any dings and dents will introduce air.

Good luck!

E

[safesheet]

E,
Thanks for your advice. I will look inside in the next week or so and post my findings. Sounds like your on the money.

[EStaggs]

Take your camera with you. Shoot some photos of the pump from both ends, getting well lit shots of the interior. Helps to get a better perspective when you are between the 14'er peaks, and Im over here as close to canada as I am to Idaho.

E

[speedboats]

http://www.hamiltonjet.co.nz/obsolete_waterjet_manuals

From here it's pretty simple to get to either the old workshop manuals or owners manuals.

As previously mentioned, the Kodiak jets are modeled on (pretty much directly copied) the 770 series Hamilton waterpump. When needing replacement parts we will often purchase items from Kodiak to replace parts in the 770. The castings for the Kodiak seem to be thinner in the wall, but they are made or superior material meaning no sacrifice in strength.