Minor issues -> carb rebuilds?

[sheardc]

I have a 1997 Seadoo Speedster with twin 787 Rotax engines, that we purchased back in July, 2009. So far it runs pretty well, but we are having some small issues that I would like to take care of before they become huge. The boat has ~125 hours on it. The fuel hoses have been changed from the grey ones to black ones. And we have run thru a number of tanks of gas, some with Startron additive in it. The engines have not been overheated (no block or exhaust discoloration) and when I bought the boat the compression on all 4 cylinders was about 130. Performance wise, the boat will hit 48 mph with just me in it and 3/4 tank of gas on a flat portion of the lake, which is fine by me.

The issues:
- both motors are mildy hard to start and stall out occasionaly until warmed up. Some smoke is seen at startup (there're 2 cycle so I expect some smoke).
- when accelerating, both engines occasionally bog down and stall out. This occurs mainly within the first 15 minutes of operation. When warmed up, it occurs less often.
- the port side engine runs a little slower (200-300 RPM wise ) to the starboard side if the throttles are set in the same position.

Would the issues above point to carb rebuilds? I do not know the repair history of the boat and can just guess at the repairs from what I have seen.
Thoughts??

PS: many thanks for the forum as I have searched around at a number of issues.

 

[seadoobutch787]

Your boat should run about 55mph with twin 787's in it. The carbs should be rebuilt along with checking the high and low speed adjustment settings, making sure they are set for factory spec if your ski is stock. I would also clip both plug wires on the engine back about 1/4 inch. All you have to do is untwist the plug boots and clip the wire back. Replace the plugs with new ones. What additive did you put in the fuel tank? Was it designed for 2 stroke engines, that might have messed with your carb diaphrams. When you take apart the carbs there will be a micro filter one in each carb, they might be plugged up with gunk, this will make the engines run ruff and later on they will seize up. Good luck

 

[kustomkarl]

Also be sure both carb throttle cables are in sync and adjusted to have full throttle position.

 

[timmyboy76]

being a 97, then you have 2-717's....yeah, think you need to pull the carbs, re-go thru them, and also, clean out the xcellerator pumps(they're mounted on the back carb, of each motor)..if motors aren't "respond'n" with initial "hit" from throttle, then I say, your xcellerator pump and fittings are clogged.

 

[seadoosnipe]

Maintenance?

I have a 1997 Seadoo Speedster with twin 787 Rotax engines, that we purchased back in July, 2009. So far it runs pretty well, but we are having some small issues that I would like to take care of before they become huge. The boat has ~125 hours on it. The fuel hoses have been changed from the grey ones to black ones. And we have run thru a number of tanks of gas, some with Startron additive in it. The engines have not been overheated (no block or exhaust discoloration) and when I bought the boat the compression on all 4 cylinders was about 130. Performance wise, the boat will hit 48 mph with just me in it and 3/4 tank of gas on a flat portion of the lake, which is fine by me.

The issues:
- both motors are mildy hard to start and stall out occasionaly until warmed up. Some smoke is seen at startup (there're 2 cycle so I expect some smoke).
- when accelerating, both engines occasionally bog down and stall out. This occurs mainly within the first 15 minutes of operation. When warmed up, it occurs less often.
- the port side engine runs a little slower (200-300 RPM wise ) to the starboard side if the throttles are set in the same position.

Would the issues above point to carb rebuilds? I do not know the repair history of the boat and can just guess at the repairs from what I have seen.
Thoughts??

PS: many thanks for the forum as I have searched around at a number of issues.

The smoking is caused by a slight amount of oil leaking past your rotary seal. When you start it, it shoud burn off. If the seals are about to go out, it will smoke bad and continue to smoke, as long as the engine is running.

You could probably rebuild the carbs. It sounds like you might have an issue with your needle valve and seat. Or, even your pop off.......but, you probably should rebuild them..........:cheers:

 

[sheardc]

Thanks for the input on this. As much as I would like to take this project on and learn more about the boat, I have other pressing issues that I have to deal with. I have a local outfit that wants to do the work; he was referred to me by the local SeaDoo dealer where the boat was originally purchased from, they do not sell SeaDoo boats anymore (just PWC). If I let him do the work, what should I include on the list of items to address that are time intensive?

-Carb rebuild, cleaning & adjustment $400
-jet pump maintenance (oil change & grease PTO shaft) $120 for both
I think I could do this myself with out much effort
-winterization $120 (fog the engines and drain & input antifreeze)

Seems like a lot of $$ and may do the last two myself. Big thing is to complete the PM so I have fewer issues next year.