What is normal compression on a stock 2001 yamaha GP800R jetski?

Well you have a few options here to try and fix this issue.

First I would check the kill switch boot and make sure that its still intact. If not then the kill switch is the problem.

Second thing is checking all the fuses

Third if all checks out ok, your going to want to run a few tests on your CDI. Once you open the front cover, there are two wires a black and a white. your going to want to disconnect those and then check spark or start. If spark/runs then its your kill switch if that does not work your going to want to get a manual and a OHM/multi meter and test your CDI

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_677dced97ad9bddf

There are too many design changes to determine the HP of an engine. Timing, compression ratio, and the type of fuel determines the HP of an engine. There is no direct correlation between the cc and an engine and the hp it produces.

you need a syphone pump to draw oil out of the oilchamber at where you fill it with oil,! i hope youve got all water out of cylinders ie removed plugs and cranked over several times and put yourfinger in plug tube and cranked over to help compress , messy job ! and got engine to run ! ?? dont rev it too high yet ! syphon oil several times with cheap 10/40 oil and just flush oil filter out with petrol each time ! You must do this till all ok without stopping a day or two and do it straight away or you run the chance of scrapping the motor as ive done this for 30 yrs ! fingers crossed ok ...

no clutch ! direct drive !! no neuteral !

piston rings bad, valves seals bad, check compression and get ready to do an upper cylinder overhaul

IS IT IN THE WATER?

Behind front storage container is a wiring harness, locate the single blue connector and disconnect, red light should be on dash now hold mode button down until it says SET. enter new code then reattach connector.

It is my understanding that the compression should be with in 10% of 225psi per cylinder.

Check the engine compression with a compression tester. It should be over 100psi,also check for hot blue spark on plugs,if not blue ignition problem.Weak Spark,but if blue and wont fire with ether the rings maybe worn,and compression to low...Best of luck to you!!!!

I have found that the yamahas kill switch is often the problem