Rotax engine cranks over without plugs, but when plugs are in it has a hard time.

[fukasz2000]

I have a 95 seadoo xp

My jet ski is cracking fine withour plugs in them, when I put plugs the starter has a really hard time to crank over.
I saw that most people just crank the hell out of it to get some oil out. And it starts fine.
MY BATTERY IS ALSO REALLY BAD, when I crank it over it drops to 7 volts.
What's the best battery to get ??

 

[mikidymac]

Best battery is the Yuasa YTX20HL-BS-PW from Amazon but the price has gone up to $99. Sealed and high cranking amps.

Your battery is bad so don't worry about other issues until you have a new battery.

DO NOT try and jump start it or you can fry the computer. Don't continue to crank it with a bad battery as it is bad for the starter and the starter solenoid.

 

[fatblockabody]

It doesn't shoot oil into orbit with the plugs out?

Start with a new high quality battery, if that doesn't solve it then rebuild the OEM starter and replace starter/battery cables with fresh marine grade cables.

 

[NickCawks]

If your battery is losing that much voltage then it's most likely your bettery.

As miki said start there

 

[fukasz2000]

Ok, here is the update. I just bought a really good battery from advance auto parts. The voltage doesn't drop when I start cranking on it.
Yes the oil shoots crazy out of the first cylinder.
I just took a look at the starter and its all rusty on the outside, but it works perfectly I belive.
What should be my next step?

 

[mikidymac]

Basically your crank seals are worn and leaking oil into the crankcase and then cylinders.

I would try to get it running and burn that excess oil out then check it every day for about a week and see how long it takes to start filling back up.

If it is a slow leak then you can put a ball valve on the rotary gear feed line and get by for a few more years.
If it is filling up in a day or two then you will have to pull the engine, take the engine apart and install a new crankshaft.

 

[fatblockabody]

Basically your crank seals are worn and leaking oil into the crankcase and then cylinders.

I would try to get it running and burn that excess oil out then check it every day for about a week and see how long it takes to start filling back up.

If it is a slow leak then you can put a ball valve on the rotary gear feed line and get by for a few more years.
If it is filling up in a day or two then you will have to pull the engine, take the engine apart and install a new crankshaft.

This exactly. Just went through this on a non start 717 xp I got cheap.

It will probably shoot out a hilariously astonishing amount of oil, good time to fill the tank back up with the recommended API TC oil. Just go get a cheap dollar general bath towel and keep folding it over and laying across the plug holes until it is relatively clean coming out. Keep taking breaks to avoid overheating the starter. It will smoke like crazy for a while when it finally starts.

 

[mikidymac]

Just to add, this can be caused by overfilling the oil tank so that the check valve can't relieve pressure and in some rare instances has been cured from switching from the wrong TCW oil to the correct API-TC rated oil.