Busted Jet Ski

The jet ski season has just started and we have already busted one ski.  Jenna was down visiting MJ this weekend.  We figured we would have an afternoon of fun on them.

As MJ left the ramp area, his ski started to bog down and wouldn’t get out of the pocket.  We could hear the engine rev, but it didn’t develop any power!  I told him it sounded like something got sucked up into the impeller.  He jumped off the machine and went under to clear the intake.  In the water he couldn’t find anything plugging the jet pump.  He brought the ski back to the ramp and together we put the ski on it’s side.  There was a 1 1/2″ nylon web strap wrapped around the drive shaft and in the impeller.  We couldn’t clear it at the ramp.

When we finally got the nylon web strap out, it was 10′ long.  There was a family at the ramp that had no clue about the water and they were trying to paddle a canoe.  Of course they flipped the canoe.  We think the strap may have been a tied down strap they used to transport the canoe and they left it in when they flipped.

MJ got lucky and sucked it up.

This morning we went back to the ramp to go out and found that the starter wouldn’t engaged the flywheel.  We could hear it spin but the engine wouldn’t turn over.  Turns out when MJ was in the water trying to clear the blockage, he got back on the machine, started it and limped it back to the ramp.  In doing so, the starter sheared the teeth off the flywheel.

Jetskis on the Navesink

MJ & I rode the jetskis on the Navesink on Sunday, 6/14. I used “My Tracker” on my cell phone to record the trip. The jetskis are older machines and I’ve always wondered the speed and distances we travel on them. Using “My Tracker”, we know exactly how far and fast we are going.
Yesterday we traveled 15.8 miles. The max speed was 48.09 mph and the average speed was 18.35 mph. The river was choppy with a lot of wake from other boats. It was a challenge to avoid the waves and get the skis moving fast. But it was fun to jump the wakes.

Jet Ski Engine Bites the Dust

One of the jet skis has been having engine problems.  Initially the engine was very hard to start.  It would turnover easy enough, but wouldn’t fire.  After cleaning the carbs, the engine would start, but then it would backfire and stall.  After backfiring and stalling twice I though I  would pull the top end apart to see if something was wrong.

Well, it turned out that one piston threw a ring.  The piston and cylinder walls were torn apart pretty bad.  As you can see the left piston is a total wreck versus the new piston that is replacing it.  Fortunately the crank shaft was in great shape.    So I m now rebuilding the top end of the engine.  The engines in the skis, because of the beating they take, are designed to make top end rebuilds pretty easy.  I bought the top end kit from SBT.  Their kit includes the cylinders, pistons, rings, wrist pins, bearings and gaskets.  While I was replacing a good portion of the engine I decided to rebuild the rest of the ski.  I’ve replaced all the fuel and water lines. Putting in a new starter.  Installing new wear ring and impeller on the jet pump.

I also had a seized engine that came from my “parts” ski.  Since I was pulling one engine apart, I decided to take a shot at pulling the seized engine apart.  The one cylinder / piston came apart easily enough.  The seized piston one ended up coming out in pieces.  Once I had 1/2 of the piston removed, the rest finally pulled away from the cylinder wall and fell apart.  In the photo I have both engines with the top end off each.  With a little effort I think I can get the seized engine back together working.


Of course it is  little bothersome to see one of your favorite toys in pieces on the garage floor.  But with a little luck it’ll be back in the water shortly.

Grrrr – I was klutzy this weekend

Saturday it was beautiful here on the Jersey Shore.  The temp was in the 70’s with blue sky.  I decided to work on the one Jetski.  I still have the engine apart because of the cracked water jacket.  I have two new water jackets with the exhaust manifold all ready to go on.  Cylinders are all honed.  I cut the rave exhaust valves to clear the pistons.  Everything was all set.

As I was setting the water jackets on the lower half of the engine, I let one piston slip and hit the exhaust baffle.  Boop went a piece of the ring on  the one piston.  Damn.  Now I’m waiting until March 20th when the new rings should arrive.  After the incident I decided to replace all the rings in the engine.

After I messed up the piston ring, I decided to replace the VTS motor.  This is a small electric motor that raises and lowers the angle of the jet pump.  The old motor had died and the case was corroded.  It was easy to replace.  Now I have to wait to finish getting the engine back together before I can test the VTS motor.

I fully expect to have both machines back into the water before this month is over.  I’m just very frustrated with myself for being a damn klutz.