New Engine - Or Just Top End? 96 GTX

[Shelato]

I have a 96 GTX. It was given to me with the top end removed, in a box of parts. The guy that gave it to me (my brother), said the dealer told him it needed a new engine. But this was over a year ago and he does not remember the specifics of the problem, other than it stopped running while out on the lake.

I can see the pistons and cylinder walls are lightly scored, and the tops of the pistons are black. I put it back together, without new seals, just to see if I could. It went back together easy enough. The electrical works and it turns over (I left the spark plug wires off). I don't hear any bad noises when I turn it over.

How do I know if it needs and entire new engine or just the top end? I was thinking of having the cylinders ground and replacing the pistons first. Does that make sense? It's my winter project so I'm not in a big hurry.

Why would the sides of the pistons be scored?


Thanks,

Dwight

 

[Dennis]

Project

I would remove the engine and disassemble it. That way you can get a good look at the crank, etc and then make a decision. You got all winter so take advantage of it. It will probably save you money too.
Good Luck,

DAWG

 

[96GTXtom]

Just did a 96 GTX myself 787 motor. Take the time and remove the motor as mentioned. If you shop around and take advantage of the "off season" pricing you can get your motor rebuilt and save a bunch! Be sure and take ALL the old fuel lines out (if they are grey still) and change the fuel valve at the same time. Flush the oil tank and lines and replave all filters, Inspect the impeller assy and use some of the savings to get a new solas product to add some extra push! I did my entire unit for $1,100 including the carbs, complete motor (done at a machine shop with new crank and pistons) and fuel system. The GTX is a great all around product. If your in the Dallas area I can even help you out in person! Have fun....Don't worry about what caused the piston scoring because there are several reasons for this. Just make it new again and you will have no worries.

 

[Shelato]

Thanks Tom and Dennis,

Tom, when you took the lower unit apart, what make you decide it needed a new crank? I rebuilt a Chevy 350 (took it to a machine shop and they bored it, put a new crank, cam, and pistons in it). I just put the heads together. I don't think I would take on the crank myself.

Also, what would have made the mechanic take the cylinders and pistons off my GTX and announce it needed a new engine? Is there something obvious he would see?

Thanks again,

Dwight

 

[96GTXtom]

The engine in your GTX like all others works very hard and runs at a very high RPM. The cyl scoring was caused by wear and stress from many hours on the lake, lack of oil, other..... Any time you have scoring the metal that came from the cyl wall has passed over the crank bearings/crankcase. I understand that this adds to the cost to your project to rebuild the crank (or replace it with a new one $500 max cost) however, it will save you money and worry for next year when your on the middle of the lake! Take it from me (learned my lesson twice over this same issue). If you cut corners now it will bite you later when you don't expect it!!!!! Weekend ruined, and you have to replace the crank anyway (adding the top end cost again plus all the time).
Have fune with the project. If you get frustrated just e-mail me I want a matching 96 GTX for my kids tomlail@yahoo.com

 

[seadoosnipe]

Dwight, if he took the cylinder heads off and then said, it needed a new motor, the only way he may have been able to come to that conclusion was by grabbing the pistons at the connecting rods and pull them up and down and wiggle from side to side.

When you do this, your looking to see if the crank is wobbling in the main bearings. If there is any deflection of movemtent, then it's worn and needs a new bottom end. A good mechanic can feel through the connecting rods, what the conditions are of the bearings.

Also, if you can roll the shaft over (I know the connecting rods and pistons will be flopping) you can feel for irregular "catches" or grinding kinda feelings in the shaft. When you roll it over, it should be really smooth.

Like Dennis said, pull the motor and split the casing. There is no gasket, so you won't have to worry about buying anything but maybe a little 30 weight oil. When you pull the casing apart to look over the crank, lean it over and dump the oil out of it. It's for the balance shaft. When you to to put the casing back together, put 1 ounce of 30 weight oil where you see the two gear cogs coming together. No more than one ounce.

If while seperating the casing, you move the balance shaft, make sure you line it back up correctly. It's timed with the crankshaft. There are two dots on the cogs that line up together............:cheers:

 

[Shelato]

Okay, I'm convinced. I'm going to tear it down.

Our extended family, 25 people, spend a week on the St. Lawrence river every year. There are 4 Seadoos and we blow an engine EVERY YEAR. They see pretty tough duty with more kids getting old enough to drive them each year. But I was on one that blew last year. The river is 1 mile wide and I was going like a raped ape accross to Canada when the coupling on the back of the engine came apart. That's not a fun feeling when your sitting right on top of it!

It would help if I learned to repair these things. We take them all to the dealer for service each fall and pick them up in the spring. Throw in 1 new engine every year and it's a little costly.

Dwight

 

[nswillin]

If you want to save some money and start doing your repairs and general maintenance so they'll run for a good while I would suggest becoming a premium member, if ya want. You will gain access to all the shop manuals seadoo makes for all the boats and pwc's. These manuals contain step by step procedures and explanations on how to do anything to your Seadoo. Also you get first dibs on all post and expert advise. We will search the earth to find an answer to your problem.:cheers: