Question

[Gary pope]

All right guys I have been working on this 95 speedster for the past two years. So far I replaced one motor with a remanufactured one from SVT, get it running great, and now I found out that I had some ri all right guys I have been working on this 95 speedster for the past two years. So far I replaced one motor with a remanufactured one from SBT, get it running great, and now I found out that I had some Knocking going on in the other one, so I made the executive decision to pull the motor out of the boat so I can inspect it, and upon pulling the cylinders off I found out that my Pistons are pretty much fried they are scorched however it did hold 120 psi in each cylinder which surprised me. Could this have been with my knocking was coming from? And also what causes these scoring issues on the piston skirts, overheating?

 

[Dr Honda]

It could be the knocking... but it can also be 100 other things. Heck... the pumps and driveshafts knock in these things.

Anyway.... the melted piston skirts are classic 2-stroke failures. You already called the problem. 120 psi compression. In a 2-stroke... as the rings wear, the hot gasses get past the rings and 1) Overheat the skirts and 2) displace the very little amount of oil that is protecting the pistons. In a 4-stroke, with oil in the crankcase... there is a lot of oil to cool, and protect the pistons as the engine wears. I tell people all the time... keep a eye on the compression of a 2-stroke. when it starts to drop... replace the rings, and deglaze the cyls. It will keep it running for a very long time.

At this point... all you can do is a full rebuild as the lower half will be getting messed up too.

 

[Gary pope]

OK I have a problem Honda, I’m sitting here trying to get my PTO off with a friend this motor and this thing is on here so bad that I sheared the keyway to the crankshaft off inside the flywheel, do you have any other suggestions on how to get this PTO taken off the front of this motor?

 

[mikidymac]

Well, you probably just twisted your crank so maybe do it the correct way?

Lock the rear cylinder with a piece of rope down the spark plug hole or better yet pull the head, insert a wooden block then torque the head back on. Now use a chain wrench and some heat and with the wack of a hammer it will spin off. Much easier with the engine still bolted to the hull.

I can't say this enough but the service manuals can be downloaded for free and will save owner's so much headache and money.

 

[Gary pope]

Yeah I’ve tried that rope trick before... that don’t work... I’ll give the block of wood a try when I get home. It doesn’t matter about the crankshaft because I’m ordering a replacement one from sbt.
The wood block trick worked... thanks....does anyone know where I can get a replacement key way?

 

[Gary pope]

I have another question...I have a 97 seadoo gts and a 95 speedster....ok, on the 97 with the 720 in it, I noticed that the water intake from the jet pump goes from the pump directly to the head at the pto side....now on the speedster, with the 657 x motors, the water intake goes to the exhaust manifold first, it does have a hose that goes from the top part of the head on the pto side to be able to hook it up to a garden hose...I guess my question is can I hook up the hose on the speedster from the jet pump to the part of the head where you can hook up the garden hose? The reason I ask is because when I run it on the garden hose it rubs cool but when it is hooked up as it should, it tends to get a bit hot and the overheat buzzer goes off.

 

[Dr Honda]

Don't run the 97 on the hose. You will destroy the driveshaft seal. It needs the lake water to cool/lube it.

 

[Gary pope]

I understand that but can I hook up the speedster with the 657x motors in it the same way?

 

[mikidymac]

No. The 720 and 650x have different cooling flows.

 

[Gary pope]

Ok. Another question is when it comes to the ignition timing and the stater, I noticed that the cases that are on the old motor don’t have any timing marks on them, what process do I have to go through to set the ignition timing? I know on my 720, it had a mark on the stater and one on the case all you had to do was line them up

 

[Gary pope]

OK let me pick your brain on this one. The little tiny hole that allows water to flow to the temperature sensor I’m thinking isn’t getting enough flow and that is what’s making it overheat, has anybody on here ever build a couple more holes to allow more water flow or reamed this whole out just a tad bit.

 

[mikidymac]

If you have an overheating issue something else is wrong, don't start drilling holes to bandaid the problem.

 

[Gary pope]

Well what can the issue be, when I run it in the driveway and a hose it as cool as ever, but when I take it out in the lake that’s when it seems to start to overheat. Another issue I’m having is somehow my float came dislodged from the baffle on the inside of the gas tank,Can you think of a good suggestion to get it out of the tank without having to pull the tank?

 

[Gary pope]

Never mind I got the flow out by Dingaling a strong magnet in the gas tank in the bowl and some compressed air around in the tank and then shake in the boat and then just Wayton, kind a like fishing and needless to say I can’t me afloat and magnet

 

[mikidymac]

Well, on the hose you are only at idle so no load on the engine for a start.

Running lean, low compression, bad timing, sand in the cooling passages, blocked hoses, worn impeller and wear ring can all cause overheating.

 

[Gary pope]

OK you brought up timing, did you see my question about ignition timing for the stator earlier?

 

[mikidymac]

I would think there has to be marks, sometimes they are under the bolt that holds it to the cases. It has been a long time since I worked on a 657 though.

 

[Gary pope]

This is the picture of the 657X, noticed there is a mark on the stator But there isn’t one on the case