20 Most Recent Yamaha Waverunner Xl 800 / Xlt 1200 Jet Ski Pwc Cover Questions & Answers

You'll see 2 small caps in the carburettor cover.
Do that fogging only in very well ventilated area ( outside thus).
Run the engine on idle, open both caps, spray as much fogging oil in both holes ( use 2 cans) till the engine stalls.
Close the caps.

Yamaha... | Answered on Nov 14, 2017

Have you tried without fuel tank cap?
Seems to me as a fuel delivery problem...

Yamaha... | Answered on Nov 14, 2017

Only of you have ran the engine out of oil...Sounds like the carbs may not be set correctly.. .Did a professional do the rebuild?..What exactly was "rebuilt".. were any parts replaced?
Sounds like the low speed (pilot jets/air screw passages may not be clean as they need to be??)
Please check the compression on each cylinder..remove the spark plugs... hold the throttle (carbs) wide open when you check this.. spin the motor for 5-8 seconds... you should get 120psi. minimum..(and less than 10psi difference).. if less, it might be time to actually rebuild the top end..(new pistons/rings/hone cyl.).. only bore it if absolutely necessary.. get it measured..

There are only 3 parts in a two-cycle carb that ever need to be replaced,,(unless they are actually broken) The needle and seat assy., the jet needle and the needle jet. ..see pic... parts # 41 = needle and seat assy. #6 = jet needle, #37 = needle jet.


The needle and seat regulate the flow of gas into the carb as the floats rise and fall..,, if they are damaged or leaking the carb will overflow with gas., the needle jet is a orifice with a specific size..The jet needle has a specific size, taper, and length..== The jet needle and needle jet work in unison to regulate the flow of gas from right off idle all the way to WFO..the needle jet/jet needle WILL wear over time causing the fuel/air mixture to become richer and richer and start fouling spark plugs..(this is more pronounced on 4-cycle ATV's)...
I hope this has shed some light on your carb situation...
Good luck...
exploded view of mikuni carb Google Search

Yamaha... | Answered on Jul 12, 2017

Make sure you are using Yamaha oil not an off brand. It does make a difference.

Yamaha... | Answered on Jul 07, 2015

Do you have a 1200 xlt ?
If yes then undo the 2 large jubilee clips on the top of the exhaust , slide it forward to access the next 2 clips on a smaller pipe , slide this forward also !
Then remove the 2 clamps on the top of the cylinder head , remove the spark plugs or they wont come off and put rags in the plug holes ! Then below where the clamps came off there are 2 bolts down between the engine and exhaust to come out , then at the rear of the engine there is another clamp , totally remove it also ! Then release the clip at the point where the exhaust goes through the bulk head and you should have a sencer wire in the exhaust , unclip it and you can then pull out the exhaust with a bit of push n pulling ! the front part of the exhaust has a water pipe under the front part and then the bolts on the manifold which the outer ones are tight against the body but you only undo and remove with the exhaust , tight squeese ! Refit in reverse order !!

Yamaha... | Answered on Feb 25, 2015

The owners manual does not provide torque specs there is an on-line manual for $5 which claims to cover torque specs at: https://www.tradebit.com/filedetail.php/141315359-yamaha-waverunner-gp1200r-service-manual-repair-2000-2002
Good luck!

Yamaha... | Answered on Sep 08, 2014

Size does not convert to h.p. You need RPM, compression ratio, efficiency, crank shaft length, number of cylinders and efficiency, valve spring force constant, valve weight, and many other variables. Horsepower is normally measured with a dynomometer (dyno). It is not calculated.

Yamaha... | Answered on Aug 30, 2014

Check the ground wire from coil to engine & the plug wire that it doesnt have any cracks which could make it short out or try another plug as they can become faulty...there is no fuse in the sparkplug wire

Yamaha... | Answered on Aug 10, 2014

if its xlt 1200 its inside the big black electric box at rear of engine ! unbolt it and remove the back cover !

Yamaha... | Answered on Jun 11, 2014

run on hose adapter and check engine is cooling by feeling the engine and exhaust system ! if ok then check intake water pipe is clear ! 2 or 4stroke?

Yamaha... | Answered on Jun 09, 2014

possible seized water pump
the one that is not working
follow it back to the source look for blockages
but personally i cannot see a blockage stopping all water coming out
so i would look more at the water pump

Yamaha... | Answered on Jun 06, 2014

which make of jet ski have you as all different ??

Yamaha... | Answered on Jun 02, 2014

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