Wave Runner GP800R engine

[AnteP]

Hi folks,

I just got a PWC for free. It seems nice and in well shape except for the engine.

It´s a Chinese copy of a Wave Runner GP800R, branded Shenqibao.

The problem was that it didn't worked so well for the previous owner, and I took a compression test, 8 kg on one ande none on the other.
Removed the head and I found out that one piston didn't looked so well, with big marks at the top of the piston.

I don't now which way to go?
Change the pistons and gaskets (provided that the rest is OK) or do a engine swap?

If a engine swap is the best, where's the best place to find a OEM Yamaha engine that can be shipped to Sweden and doesn't cost a fortune ?
In Sweden there's not so many of these Wave Runners and even fever of the engines.

The Chinese engine (and the whole PWC) seems to be an exact copy of Yamaha's, referring to my workshop manual for the Yamaha Wave Runner GP800R, so if I'll go
´´the changing parts way´´, I'll buy them for the Yamaha.

Best regards
Ante

[turboman412]

Pictures?

[AnteP]

Pictures?

Pictures of the engine or all of the machine ?

[steve45]

Welcome aboard, AnteP!Free PWCs are usually the most expensive ones!I'd love to see pictures, too! Pictures of everything. Hull, engine, gauges, jet pump, etc.

[AnteP]

[attach=config]471821[/attach]

[steve45]

Thanks, AnteP!Very interesting. Not much information on Shengqibao, but I saw some 4-wheelers with that name. It may actually have a re-branded Yamaha engine.Where are you located?

[AnteP]

Thanks, AnteP!Very interesting. Not much information on Shengqibao, but I saw some 4-wheelers with that name. It may actually have a re-branded Yamaha engine.Where are you located?

That's correct. It is a re-branded Yamaha.
My workshop manual for Yamaha GP800 matches my engine exactly.

My idea is to buy Yamaha parts and fix the Shenqibao, or to buy a complete engine and do a swap.

The question is what is the best to do ?

I'm located in northern Sweden.

[steve45]

Yes, you said that you were in Sweden. Sorry about that.If you can buy a complete engine, that would be easier and you would be certain that all the parts work together. However, you really won't know the history a replacement engine. If you rebuild it yourself, you'll have to purchase all the individual parts. I don't know how easy it is to buy parts where you are. It would suck to be waiting for months for a bolt or a gasket.Keep in mind that a lot of parts are on backorder because of Covid.

[AnteP]

Yes, you said that you were in Sweden. Sorry about that.If you can buy a complete engine, that would be easier and you would be certain that all the parts work together. However, you really won't know the history a replacement engine. If you rebuild it yourself, you'll have to purchase all the individual parts. I don't know how easy it is to buy parts where you are. It would suck to be waiting for months for a bolt or a gasket.Keep in mind that a lot of parts are on backorder because of Covid.

I've found a couple of engines on Ebay, for appr. 1000$
Also some piston sets complete with gaskets for appr. 200$
All located in the US.
It is alot cheaper than here in Sweden, and I have no problem waiting a few weeks for delivery.

I'm going to take my engine out and tear it down a bit to see if it is healthy enough to rebuild.

Otherwise I'm in to take a chance with a used complete engine.

Both PWC's in general, and parts for them, are expensive over here, so if I have to invest say 1500$, it's still a cheap PWC since I didn't pay a dime for it.

Ante

[steve45]

If you repair the old one, you really need to determine what caused the failure. Usually it's either a plugged up carburetor, or an oil hose came off, or it overheated. Be sure to pressure test the crankcase when you put it back together.If you buy a complete engine, see if they can give you compression numbers. Also some pictures of the crankshaft and cylinders. They can remove the carbs and take pictures of the crank through the reed openings. They can take pictures of the cylinders through the exhaust ports.You should overhaul the carburetors. Use ONLY original Mikuni parts (assuming that they are Mikuni carbs). Lots of people have had trouble with off-brand carburetor kits.Keep us posted on your project!