Super Jet Airleak with no airleak?

[McDog]

This xs771 motor with 44 blackjacks has been a nightmare so far. No ones fault but my own I might add.

So far it has seemed lean and not tuned correctly. Then it sunk, hydrolocked and busted a set of reeds. Then it was discovered during continued difficult tuning that one of the fuel lines was slit on the inside where it connected to the intake on the carbs. It was leaking some and definitely pulling air in. New fuel line seemed to fix the problem and it was spot on.

Today I put my wife on it for the first time and it was perfect for about 20 minutes. Then I see her by the dock and get the "something is wrong" look. Suddenly the ski seems to have a huge airleak. Lean as hell feeling and will go if you dump some fuel in with the primer. It is also making a weird vibrating or clicking sound around the carbs that I cannot find. It also revs to the moon when you jump and get air in the pump.

I pull the motor and it pressure tests fine. I pull the intake and the reeds look perfect. Now I'm tired and stumped. Maybe something inside the carbs?

 

[D-Roc]

how did you leak test?

 

[McDog]

Rubber plugged the factory pipe exhaust manifold hole and the two openings in the boyesen intake with the carbs off. Plugged one of the pulse line nipples with fuel line with a golf tee in it and pressurized through the other with a contraption Waternut made with a psi gauge at 10 psi. I also sprayed it down with windex looking for any air bubbles and found none.

 

[D-Roc]

did you pull the flywheel cover?

 

[McDog]

Not this time. I did before I originally installed it. Are you thinking spontaneous crank seal failure?

 

[D-Roc]

and clinky bearing sound. or your carbs are just not tight and rattling around. but you would have noticed that removing the carbs to pressure test. maybe take a look under the cover, i know, it maybe a sad sight but you won't know for sure until you check.

 

[McDog]

Carbs were not loose. Flame arrestors either. I had my hands on everything to see if that was it.

I guess the hydrolocking could have damaged the crank too. Delayed somehow? This sucks.

 

[D-Roc]

yes my friend, a water logged ski is not good and when i hear a reed was broke, well i take it the ski did not get run proper after the drink. I know this situation all too well, the sun is down, you can't get it to fire up proper, you take it home, spend an hour breaking down some stuff to find a broken reed. work tommorrow, no reed, now what? I tend to use quicksilver oil because it is cheap, i fill the motor. gotta do it. I have not done this and bearings go or the rod lets loose. not cool. usually on the next ride or shortly after. But you have not opened it up yet so go check that out first before you start hitting the bottle. haha.

 

[McDog]

Pulled the flywheel and pressure tested again. I even turned the crank over several times while spraying it with windex and no bubbles. Crank turns smooth. Pulled carbs apart and still no problems. I'm thinking I should go back to clear fuel lines with a new filter. I had tried used oem lines because of the longer longevity but right now it is the only thing I can point my finger at as a possible problem. Any more ideas are welcome.

 

[McDog]

I had broke the motor down and used a whole can of wd40 on the crank and cylinders. It was sort of running for a little while but had exhaust coming out of one carb from the broken reed. Then it sat for 36 hours before I got borrowed oem reeds and got it running again. I'm pretty sure I avoided any rust issues. Fresh water too. Always possible though.

 

[tor*p*do]

go get some cheap azz black fuel line from advance or auto zone
re-run the lines and see if it goes away
I will not run clear lines due to brittleness, cracking and leaks

 

[McDog]

I have some of that too. It doesn't last as long as oem either.

 

[D-Roc]

that is all good news, i have had great results with filling the motor vs not doing it, haha. it is messy but well worth it. so if your crank and bottom end is all good and motor is air tight what is next? did you drain your fuel and clean the carbs and lines all out? sorry for asking, it seems like you have checked alot already. what about the water cooling circuit, did you leak test that?

 

[McDog]

I plan to put it in with all new fuel lines. I never thought to leak check the water system. I don't really understand why I would need to. Plenty of water coming out pissers with dual cooling.

I did have a tiny exhaust leak from a tiny crack in the weld line on my limited pipe where I dented it to get some clearance with the gas tank. Plan to jb weld it. Could have contributed to muddy up the picture.

I still dont understand the wierd noise. Could still be a crank bearing thing but it sure turns smooth.

 

[D-Roc]

mine turned smooth but it was a bad seal too, you could tell by looking at it that it was bad. yours would be sealed but i don't know about your bearing. probably fine, i never used wd 40 in the bottom end. the cooling system could leak air and water if there was a crack. 61x cylinders crack. its easy to check.

 

[D-Roc]

also i like the idea of all new lines, it could be as simple as that! that would be ideal. my small engine dealer has the yellow tygon stuff and it lasts for 3 seasons if you like yellow, it is not cheap but it is nice to work with.

 

[sportfish258]

How did you sink it ? You Macon boys have had a rough season so far.

 

[Waternut]

Might be worth going with the clear fuel lines for now. They'll be junk by the end of the season but at least you'll know what's going on while you're trying to decipher the problem. Tractor supply sells some.

 

[McDog]

Novice female rider let it turn upside down and wasn't strong enough to turn it over. Scupper let air out and swamped it. Could have happened to my wife too so I went ahead and plugged the scupper for now. The wdk pole is pretty heavy and acted like keel in the up position.

 

[Sanoman]

that is all good news, i have had great results with filling the motor vs not doing it, haha. it is messy but well worth it. so if your crank and bottom end is all good and motor is air tight what is next? did you drain your fuel and clean the carbs and lines all out? sorry for asking, it seems like you have checked alot already. what about the water cooling circuit, did you leak test that?

Can l post dump on this same subject of soaking the crank? This pertains to Hornedogg's crash over four weeks ago.He got his ski back friday from the law still filled with water.He pulled it,drained it,and then filled it with oil.l saw the crank yesterday and it "seems" to turn smoothly,l didn't see any signs of rust, (still filled with oil) but l have my doughts as to whether it should be run before being professionally checked.John feels it is ok.Comments?