1998 GTX RFI won't run after sitting for years

[SD-Surf]

hello all,



I just bought a 1998 GTX with the 780ish cc RFI engine. it's super clean and has a great service record history. It hasn't been regularly used in over 5 years. It was started once or twice a year in the last five years. Now It will not start on its own. It does however fire right up and runs well for a few seconds with starter fluid. To me this is clearly a fuel issue but im am not familiar with the RFI engine at all and was hoping I could get some advice on where to start. I was thinking fuel pump or injectors. Any advice would be greatly appreciated, thank you!

 

[mikidymac]

The RFI (Rotax Fuel Injection ) Spot

 

[etemplet]

Yes, fuel injection is a good first test. You're looking for 58psi. Your pump should come on for a couple of seconds when you insert your key. You can hear it. You may just have bad fuel in there which is understandable. I remove the fuel canister and pump out the fuel tank... get it good and clean. Replace the fuel filters on the canister and make sure the fuel sending unit is making good contact while your in there. I clean it with a pencil eraser and take readings at the plug on the fuel sending unit to make sure the signal is good. Make sure you are getting 5 volts to the fuel injectors. Good Luck !!

 

[SD-Surf]

fuel pressure was good. compression was bad. 20 psi in forward cylinder. took the head off and it looks like part of the ring broke off and smeared the corner of the piston. next question is, do I need to take the motor out to do a top end rebuild?

 

[etemplet]

You can do the top end in place... I did that a few times on different skis. Now I pull the engine and put it on the table. I remove the rotary valve cover to check condition and clearances, I remove the mag cover to have a look inside to check for corrosion and wire condition. I also get a better look at the crank and I flush the bottom end and soak it in oil. Then of course I clean, sand and paint the engine. Don't forget to replace the brushes in the starter. No surprises or at lease... fewer. LOL

Physically it sn't a problem to remove the cylinders and pistons on a RFI. I've also done top ends with the engine in place on 951 Carb and DI skis. Good Luck !!

 

[SD-Surf]

Thanks for the advice! I got the cylinders off and one is in rough shape. The sleeves were bored .5mm over on the last rebuild and I’m worried a standard increment of .25 mm more will still leave the bad sleeve with grooves. Going to max them both out and bore an additional .5 over for an 83mm bore.