possibly running on one cylinder

[nate6231]

im test driving my uncles boat a 94 kenner pro skiff, w/94 evinrude -40. I changed the gas and plugs, it ran fine on the hose. I put in yesterday, full throttle was 9mph it eventully got up to 18 after a little while, it is supposed to go 35mph. back home, on the hose, with the motor running i disconnected the the top spark plug boot and it died, put it back on, restarted it, disconnected the bottom boot, it ran uneffected. i touched the disconnected boot, it shocked me and i could hear it sparking. any suggustions?

please help.

 

[Silvertip]

Re: possibly running on one cylinder

It probably wasn't running fine on the hose. You do have a fuel problem. Bottom carb fuel inlet needle is probably stuck shut or the carb is gummed up. With the air box removed, squirt a fuel/oil mix into the carb. If it begins to fire you found the problem. Carbs need to be removed, disassembled, soaked in carb cleaner, blown out with compressed air and reassembled with new kits. Spraying carb cleaner through the carb does nothing except clean the throttle bore so don't waste your time with those products.

 

[F_R]

Re: possibly running on one cylinder

Very possibly the bottom carb is the problem. However, don't be going off thinking the spark is ok on the bottom cylinder just because it shocked you. That is NOT a spark test. Also, you say you could hear it sparking. Where? It very well could be arcing out somewhere instead of jumping the spark plug gap. You need to rig up a 7/16" spark gap and see if it will jump that. Anything less is not a spark at all. I don't know about you, but a voltage that will jump 7/16" will knock me right out of my socks! If it will jump 7/16" and you are sure the plug is good, THEN you can move on to the carburetor.

 

[nate6231]

Re: possibly running on one cylinder

i pulled off the air box, with the motor running i sprayed the mix into the bottom carb, it fired up like you said, i tryed the same thing on top just to see what would happen and it died. so i guess it is the bottom carb,
can you tell me a rough estimate if i fix it myself, and if a shop does it?

thanks,
nate6231

 

[tashasdaddy]

Re: possibly running on one cylinder

you can get carb kits, here at the iboats store. shop going to charge you $200 to take the cover off. when you done do a decarb, youcan use seafoam deep creep, and from now on add seafoam fuel additive to the gas along with oil.
http://www.boatsetup.com/Decarb_Carb.html