Winter Project Seadoo 720 Build

[Seadoo4me]

I've started collecting engine parts from Ebay to build a replacement engine for my Challenger. The PO threw in a WSM crank rebuild kit and a WSM Platinum piston kit when I bought the boat. I plan on installing a WSM rotary shaft since my engines are leaking from the shaft seals. Both motors have new carbs already. I've read up on performance mods (Group K) and Mr. Bill and aside from port matching all intake and exhaust surfaces I'm likely to have Group K mill the heads and call it good. Since my pumps have stock impellers I think upgrading to Solas props will give me better performance w/o affecting reliability. The PO did liners and pump rebuilds 2 years ago. Does this sound like a good plan or is there something I'm missing ? All rubber hoses are being changed out now and I'm replacing the starter cables also since they're corroded...

 

[tdonoughue]

You are taking it in salt water, I assume, as you have corrosion on the cables? Replacing the hoses is good--you may consider replacing the clamps with stainless ones while you are at it.

Have any pics?

Not too familiar with the SeaDoos. What is the condition of your impellers? If they are still good, you may be able to re-pitch them and save a buck there.

 

[Seadoo4me]

Boat came from Florida originally so I assume it saw salt down there. The guy I bought it from used in fresh only he claims. I've put new-ish oil pumps on both motors, replaced a rotary valve and cover. This thing is a hot mess, both engines had mismatched hardware and some very rudimentary "repairs" done incorrectly. I havent even looked at the pumps yet sort of afraid to honestly. I'm going to change the oil in them and run thru this season unless I find something really bad. Both motors have good compression thankfully.

 

[tdonoughue]

Good compression goes a long way. When you check the impellers (eventually you do have to look), also be sure to check the intake path--that it is smooth. At that age, caulk and stuff may fail and leave gaps and things resulting in cavitation. It will have you thinking your impellers are bad when really you just need a little silicone caulk...

 

[Seadoo4me]

I plan on dumping the pump oil and checking for metal. I read up on Group K website about the pump shoe and shaft protector issues. PO did say props had some nicks so I will pull both pumps this fall and replace with Solas. New carbon shaft seals as well while everything is apart. I've lost some water time getting everything these guys botched up repaired correctly. Hopefully nothing too hacked up under her but the ineptitude of prior 'mechanics' repair work has been glaring and disturbing so who knows...