welp....time for a rebuild

duckman11 · Post by **duckman11** » 17 Oct 2017, 01:28

well looks like I have started my jet jon project with a dud engine.

I purchased 2 1995 Kawasaki 900zxi off craigslist for $400.
One of the skis has a beautiful hull and one had what i was told, a running engine!
So i figured $400 for......
2 pump assemblies
2 ignition control boxes
2 stators
2 sets of gauges and controls
6 carburetors
and a complete running engine wasn't a bad deal.
But with compression of 80psi PTO cylinder, 80psi center cylinder and 60psi at the front cylinder....looks like time for a rebuild. Luckily enough the cylinders are not scored and the head domes are still in great shape

Do y'all have any tips on doing a rebuild?
Do i need to put any type of silicone between the case/cylinder gasket?
What are some brands of top end rebuild kits that i need to stay away from?
What kind or ring compressors are y'all using?
When honing the cylinders.....what is the FINAL stone grit i should use?

i know someone is going to say "check out greenhulk" but id like y'alls input.

thanks in advance

handyandy · Post by **handyandy** » 17 Oct 2017, 12:14

Do you have any knowledge of rebuilding engines to start with? Do not use silicon to seal the block halves if they make up the line bore for the crankshaft. I don't know your engine at all, but I know for outboards where the block splits the crankshaft rides in between the two pieces you do not use silicon. You use a specialty loctite sealer that reddish in color I prefer loctite 518. It doesn't take a lot just a thin layer as you just want a enough to seal not ooz out when the halves are torqued together.

duckman11 · Post by **duckman11** » 17 Oct 2017, 19:12

I do have some knowledge in regards to rebuilding an engine...however 90% of that knowledge is with diesel engines.

I have a Kawasaki service manual that I printed off the interwebs but I believe the photographs were taken with a potato so its very hard to distinguish most things

CedarRiverScooter · Post by **CedarRiverScooter** » 17 Oct 2017, 22:02

I think you are referring to jug-to-block gaskets, I would guess they have actual gaskets. My Polaris does.

SBT is a good place to buy parts. They could tell you what grit to hone with. If the jugs are not scored, you might be able to just break the glaze & call it good.

I just used a big hose clamp for a ring compressor.

I used threaded rod & various sockets to pull in the wrist pins. Maybe they are supposed to slip, but mine didn't.

You might want to replace crank seals, as leaky ones are a big problem. On mine, I had to split the case for that. I used '1210' case sealer.

Inspect the reeds while it is apart, mine had cracks starting.

Fuel pump & carb rebuild is recommended too.

PWC 2 strokes have a hard life!

handyandy · Post by **handyandy** » 18 Oct 2017, 09:35

jugs to block should have gaskets once again don't use silicon. I don't know what jet ski engines are like if they use main caps like a car engine or if the the block has to halves that split like an outboard engine and have to be sealed.

duckman11 · Post by **duckman11** » 18 Oct 2017, 19:59

thanks cedar!! and all gaskets and seals will be replaced.
I will also do a pressure and vacuum test before power ever touches the starter!
I think I would rather spend the extra $$$ on an SBT kit VS something off of Ebay

And Andy most PWC engines have 2 crank case halves....an upper and a lower. So there aren't actual bearing caps like you would find in a small block chevy

handyandy · Post by **handyandy** » 19 Oct 2017, 10:17

duckman11 wrote:thanks cedar!! and all gaskets and seals will be replaced.
I will also do a pressure and vacuum test before power ever touches the starter!
I think I would rather spend the extra $$$ on an SBT kit VS something off of Ebay

And Andy most PWC engines have 2 crank case halves....an upper and a lower. So there aren't actual bearing caps like you would find in a small block chevy

If that's the case use the loctite sealer I mentioned before on those crank case halves you do not want to over do it on that sealant either as that will throw off your clearances between the crank and the block halves.

duckman11 · Post by **duckman11** » 09 Jan 2018, 02:43

update 1/9/18

engine is back together and by the grace of sweet baby Jesus this thing somehow cranked...and ran...and idled after about 30 sec of cranking. motor fires right up with just a bump of the starter now!

I also picked up 2 14ft jon boats and a trailer for 100$.

I need to figure out how to post pics

CedarRiverScooter · Post by **CedarRiverScooter** » 09 Jan 2018, 09:14

Congratulations on engine rebuild.

It's a good time of year to build, you're not missing anything on the river (at least where I live).

Hopefully you have a heated shop to work in.

A 900 engine in a 14ft boat will be a thrill ride.

duckman11 · Post by **duckman11** » 09 Jan 2018, 21:12

I'm in north Texas and the sand bass and crappie run up the creeks is just around the corner for us.

The hull I have is a 14ft 42" v-bow boat, it is weird shaped to say the least! It is shaped like a piroge....completely flat bottom with about a 2" rise from the bottom of the transom to the bottom of the bow. Its dang near flat both sideways and lengthwise! So what im thinking about doing is cutting sort of a pacman mouth in sides over the front 4ft and bring the bottom of the boat up more to give me more bow rise. Its gonna squat in the rear like all of these boats do......but having a vertical knife edge shaped bow just inches above the water aint gonna last long in the timber I run in.

CedarRiverScooter · Post by **CedarRiverScooter** » 10 Jan 2018, 10:25

Sounds like a unique hull - how about a photo?

In my experience, with the engine weight near center of boat, they run pretty flat. Certainly there is no squatting or bow rise during hole shot.

duckman11 · Post by **duckman11** » 10 Jan 2018, 20:13

cedar I don't know how to post pics.....but I will look it up

CedarRiverScooter · Post by **CedarRiverScooter** » 10 Jan 2018, 21:33

There is an Img button for loading pix on my browser - but I use a laptop.

I have heard phones as PIA for pix uploads, so good luck if that is the case.

turbotodd · Post by **turbotodd** » 30 Sep 2018, 19:35

The main issues we saw with jet ski engines is water intrusion.

Most people think that if water gets into the engine, it scores the cylinders. That's true. But it's only a small part of what actually happens.

It also removes the lube oil film from everything.

And among other things, when water is hydraulically locking a cylinder, the crankshaft can/will spin. Thus, then the port timing is off on that cylinder, the ignition timing is off on one or more cylinders, the engine vibrates, it vibrates itself to death, holes pistons, runs hot, doesn't run at all, sometimes it's just a bent rod other times (more often than not) the crank twists and, sure you can throw it back together and it'll "run" but for how long?

This is where some companies who sell rebuilt ski engines don't check things well enough. That crankshaft has to be perfectly indexed. If it ain't done right, it'll run fine but eventually will develop problems. When I was in the ski business, you wouldn't believe how many of these engines I had to build and oftentimes REbuild. Especially the ZXi's, 750, 900, 1100-and the 900/1100 were my least favorite. They never seemed to last more than 20-50 hours. If it wasn't the engines, it was that dad gum trim system which sucked from day one!

I know where there's a 750 Xi for sale, cheap, and it runs (I rode it across the lake)-and thought about doing a jet jon project with it. But I hate kawasaki's ski engines so badly that I won't even buy this thing dirt cheap. I MIGHT if he paid me to take it, but that'd be the only way. And I have a use for a jet jon.