98 770 TSL Mikuni 38/37 carbs ?

engr146 · 02-02-2010, 05:28 PM

What size needle and seat ,do I order for my 770 stock carb.bought rebuild kit,needle and seat not included.
THX

dank · 02-02-2010, 07:42 PM

Pull the old one out of the carb it will be stamped on the side. Normaly a 1.5 or 2.0 in the 38's

jetski9010 · 02-02-2010, 09:08 PM

mine had 2.0 n/s in my 770.

engr146 · 02-02-2010, 10:22 PM

would the pto side seat/needle be different than the mag side! I'm getting ready to finally replace the holed PTO piston,I'am 80% positive ,The bad carb caused it,but I think I should check the reeds,I know the carb was dripping fuel,but also,I noticed a little fuel spitting up out carb,would a dripping carb.also spit the dripping fuel up.out the carb.(before hole made in piston)
I'm cleaning /rebuilding carbs as needed.

jetski9010 · 02-03-2010, 07:02 PM

have you replaced the crank seals in the motor? A lot of time the crank seal will wear out on the PTO side and cause it to run lean causing damage.

dank · 02-03-2010, 07:48 PM

The needle and seats would be the same.

engr146 · 02-04-2010, 04:48 PM

My plugs never looked lean,I was running,50:1 premix along with the oil pump @ time of piston (Holed) I could not get bottom screw out of oil pump.so I ran ski,for the last week in September planning to install block off kit when I pulled ski out of water for winter.The carb was definatly a problem.and I planned on cleaning/rebuilding them over the winter,But piston did not last.150# in other cylinder.

jetski9010 · 02-06-2010, 03:59 PM

If it was only running lean in the high RPM range because the carb needed cleaned it will affect the plug readings once you come back down to low-idle speeds. If you were to do a plug chop it would more then likely show signs of being lean.

engr146 · 02-07-2010, 01:45 PM

I just bought ski late Fall,and ski was running badly,I know It was the pto carb,I could see fuel dripping,The week before I pulled ski out for winter,I went for a ride ,and wile running @ higher RPM ,ski bogged down ,and would not go over 2000 rpm,did compression check,150# mag / 0# pto looked thru spark plug hole and seen pea size hole in piston.
I plan on pulling head and If cylinder is ok,just replaceing PTO piston and rebuilding carbs.Top end was done ,previous winter,
What are your thoughts!!

engr146 · 02-19-2010, 02:29 PM

are the mikuni sbn 38/37 for a stock 98 770 tsl 2.0 needle and seats push in type or old type need to order.parts!!

Pulled head exaust and carbs, tried to pull jugs,they won't come off,all top bolts off and bottom nut above srarter,backed off as much as possible unil cylinder is raised.I let studs soaking,dank says,to hit with mallet side to side.has anyone ever had to use a slide hammer to loosed cylinder from base.Am I missing something ?? .