Superjet Broken Reed Pedal

[John_Ciocca]

My ski started running bad a few weeks ago. It acted like there was some sort of carb problem because it would not obtain max RPM. It is the kind of power like running on one cylinder (but both are firing), max RPM of maybe 4k.

I tore into the carb and all seemed well. Then I took off the intake and one of the carbon Tech reed pedals on the front cylinder intake was broken.

Can a broken reed pedal cause the engine to not achieve max RPM? I think not because at max RPM the pedals are open correct? So it would be a throttle response problem not a high RPM issue correct? Am I wromg? I am just thinking I have another issue.

(I have not repaired the broken pedal yet)

JC

 

[Matt_E]

The symptoms you are describing are 100% attributable to the broken reed.
Fix that, and your ski is back to normal.

In fact, why would you think you had other issues? It started acting up one day, and then you find a broken reed. Seems like a good cause & effect to me, no?
Healthy reeds are absolutely essential to engine performance. I am 99.9% sure that's your only problem.

 

[RideItLikeYouStoleIt]

Reeds arent open all the time either. They are open more often at full throttle but not open the whole time.

 

[John_Ciocca]

The symptoms you are describing are 100% attributable to the broken reed.
Fix that, and your ski is back to normal.

In fact, why would you think you had other issues? It started acting up one day, and then you find a broken reed. Seems like a good cause & effect to me, no?
Healthy reeds are absolutely essential to engine performance. I am 99.9% sure that's your only problem.

I think I might have another issue because I didn't quite tell you the whole story. I subbed the ski and all four motor mounts broke. I repaired that and then I had the RPM issue. I troubleshot some more and found the broken reed.

It just seems weird that the motor mounts and the reed all broke at the same time. I thought that if a reed is broken, it would mess up your idle and bottom end. But once you pinned the throttle it should not affect top end because at WOT the reeds are open. Is my thinking correct?

 

[John_Ciocca]

Reeds arent open all the time either. They are open more often at full throttle but not open the whole time.

But would a broken reed limit you RPM to approx 4K? That is the question.

 

[Matt_E]

Yes it would, absolutely.
Broken reeds destroy performance from bottom all the way to the top. The motor needs good sealing of the reeds in order for air/fuel charge transfer into the combustion chamber to work.

Replace the reeds, and I 99.9% guarantee your problem will be fixed.

Btw, what sort of sub from hell breaks motor mounts?

 

[SJBrit]

Like Matt said - don't forget that the sole purpose of the reeds is to act as a one way valve for your intake side, otherwise you'd have exhaust gasses being forced back that way after combustion. A broken reed screws the whole thing up. They open and close on every cycle, regardless of RPM.

 

[John_Ciocca]

Yes it would, absolutely.
Broken reeds destroy performance from bottom all the way to the top. The motor needs good sealing of the reeds in order for air/fuel charge transfer into the combustion chamber to work.

Replace the reeds, and I 99.9% guarantee your problem will be fixed.

Btw, what sort of sub from hell breaks motor mounts?

Thanks Matt_E, I was hoping for a strong technical confirmation.

As far as the submarine. I think I had a few broken mounts in the first place and the sub (which included me going over the bars) was the straw that broke the camels back.

JC

 

[michaelbrenner]

I witnessed this sub, and although I can't do one and think they are cool, made me not want to try! The motor was fully tilted to the side and the coupler was all cock-eyed of course. Happened at about 8am on 4th of July!!! Nice.

 

[wydopen]

Thanks Matt_E, I was hoping for a strong technical confirmation.

As far as the submarine. I think I had a few broken mounts in the first place and the sub (which included me going over the bars) was the straw that broke the camels back.

JC

you cant ride with broken mounts:chairshot:

 

[Mouthfulloflake]

some one stole my carb, and now my ski wont start.

Matt_E,

do you think its a jetting problem?

or should I buy a new impeller?

hehe..

IM kidding.

my ski still starts, although someone DID steal my carb.

 

[Matt_E]

Ah....I seem to remember that. Didn't you let someone borrow it?

 

[Mouthfulloflake]

yes, dammit.

i would normally loan folks parts to help them test, or troubleshoot, but this one guy that wont return my carb has basically burned me on that.

why in the hell does Phill need a stock head anyway?

 

[Flash-FX]

I witnessed this sub, and although I can't do one and think they are cool, made me not want to try! The motor was fully tilted to the side and the coupler was all cock-eyed of course. Happened at about 8am on 4th of July!!! Nice.

When doing "deep" subs or filling your motor compartment with excess water... while it's running will certainly destroy reeds. (You can compress air but not water). Get it?

And...after you get it running thinking it's all good, salt water sludge still lurks in the reed cage area..for weeks. Rust never sleeps.:Banane35:

Been there...done that. $$

 

[Mark44]

yes, dammit.

i would normally loan folks parts to help them test, or troubleshoot, but this one guy that wont return my carb has basically burned me on that.

why in the hell does Phill need a stock head anyway?

What is this posters name? We can all PM him telling him to send your carb back this really sucks someone would do this someone has to know him.

Mark44

 

[Mouthfulloflake]

there is a thread , called, "got my super jet running, but not well" or something like that.

the dude hasnt logged on in a while.

I told him months ago, I wanted the carb back or $50.

he said he had a lone on another carb and asked me if he could keep it 2 more weeks.

I said " sure, then its $50 or my carb back"

that was like in March or something.