cylinder number 2 very lean on Superjet

[pioui1]

I have a Superjet who is running very lean on Cylinder number 2 , if you look at the pictures you will see that the number 1 is good and the second one is very lean , when I did my testing , my low speed reading was good on both cylinder ,but when I go from mid to high the reading , it is very lean on the cylinder #2, the pictures are the mid rang reading, it is worst on the high speed reading

My set up is 135 high speed jet, stock low speed jet, stock Needle and 80 gram spring, the starting set up was low speed screw open 1 1/4, high speed open at 1 turn,
But now the rear carb of cylinder # 2 is 1 1/2 high speed screw and low speed is at 2 1/4, front carb or cylinder #1 high speed screw is at 1 turn and low speed is at 2 turns

the B-pipe screws
bottom is close
the middle open1 3/8
the top open 2 turns

I think the crank seal might be the problem

 

[kevbo]

All single carb engines will have one cylinder hotter than the other. Tune the hot cylinder and let the cold one do whatever it wants. Multiple carbs can be adjusted to meet each cylinders needs.

 

[waxhead]

I have a Superjet who is running very lean on Cylinder number 2 , if you look at the pictures you will see that the number 1 is good and the second one is very lean , when I did my testing , my low speed reading was good on both cylinder ,but when I go from mid to high the reading , it is very lean on the cylinder #2, the pictures are the mid rang reading, it is worst on the high speed reading

My set up is 135 high speed jet, stock low speed jet, stock Needle and 80 gram spring, the starting set up was low speed screw open 1 1/4, high speed open at 1 turn,
But now the rear carb of cylinder # 2 is 1 1/2 high speed screw and low speed is at 2 1/4, front carb or cylinder #1 high speed screw is at 1 turn and low speed is at 2 turns

the B-pipe screws
bottom is close
the middle open1 3/8
the top open 2 turns

I think the crank seal might be the problem

Why do you have the pipe setup like that. You are leaving so much power and throttle response on the table

 

[pioui1]

Why do you have the pipe setup like that. You are leaving so much power and throttle response on the tabl

Check each Cylinder Compression first. Maybe the ADA O-Ring Gasket is leaking.

Check both Carbs for bad Parts such as worn Diaphragms or clogged Internal Filters.

Last, do an Air Leak Down Test to find any Air Leaks.

By the way, how many Cooling Lines from the Pump are there?

And how many Overboard Bypass Pissers are there?

Post Photos of whole Engine Bay.

HEllo and thank you very much

the compression is 180 for the # 2 and # is 185,

I open the carbs and they were very clean,

I put a new gasket with 1211 bond in between the carbs the manifold and it did not work either,

I will put a picture of the whole engine bay tonight

 

[pioui1]

Check each Cylinder Compression first. Maybe the ADA O-Ring Gasket is leaking.

Check both Carbs for bad Parts such as worn Diaphragms or clogged Internal Filters.

Last, do an Air Leak Down Test to find any Air Leaks.

By the way, how many Cooling Lines from the Pump are there?

And how many Overboard Bypass Pissers are there?

Post Photos of whole Engine Bay.

 

[pioui1]

thank you for your time, for the water cooling ,the cooling tube coming from the pump is no longer 3/8 is it now 1/2 that is why you see the t or Y,

there is no Kink in the cooling line

 

[kevbo]

One line in and two out is fine as long as the in line is at least 3/8" and the two outs are 1/4". Make sure the pisser stream is solid! ADA heads are prone to leaks and any combustion gas in the water jacket will make the head hotter. Each carb must be tuned individually. If you set both carbs the same one cylinder will have higher combustion temps..

 

[badvinny]

Possibly a leaky crank seal on the rear .

 

[pioui1]

It has ONE 1/2" Cooling Supply Line with TWO 3/8" Overboard Pissers...

Yes

 

[pioui1]

One line in and two out is fine as long as the in line is at least 3/8" and the two outs are 1/4". Make sure the pisser stream is solid! ADA heads are prone to leaks and any combustion gas in the water jacket will make the head hotter. Each carb must be tuned individually. If you set both carbs the same one cylinder will have higher combustion temps..

I don't really understand,sorry , the pisser stream and also when you say adjust
the carb individually , just the high and low speed screws adjustement

 

[pioui1]

Possibly a leaky crank seal on the rear .

I thought so too, but when I start the engine and I spray brake cleaner on the base gasket and the crank seal , there was no change in RPM

 

[kevbo]

Each cylinder will require a slightly different carb tune in order to achieve the same combustion temps.

 

[pioui1]

I am very surprise should I put a bigger jet for the high speed jet for that cylinder

 

[kevbo]

YES, that is what the factory does on stock boats.

 

[pioui1]

thank you

 

[Mike W]

Just went through this on my ‘17 RN. After I fixed my tuning issues (bad needle and seats) I stumbled upon this write up by Group K. Very interesting read. I richened up my rear carb by 1/4 turn. Problem solved.

Rear Cylinder Piston Seizures – Group K

groupk.com

 

[pioui1]

thank you I will read it

 

[pioui1]

Just went through this on my ‘17 RN. After I fixed my tuning issues (bad needle and seats) I stumbled upon this write up by Group K. Very interesting read. I richened up my rear carb by 1/4 turn. Problem solved.

Rear Cylinder Piston Seizures – Group K

groupk.com

I will probably need to put a bigger high speed jet for the back cylinder