will only run on choke

[tigerking]

I have a 1991 48 hp SPL that will only run when choked. Pumping the ball doesn't result in any change. Compression is good (113 and 110) and there doesn't appear to be any leaks in the fuel hoses. I have now pulled the carbs twice and blown each jet with a can of carb cleaner until I see it come out the other end. Float is parallel and drop is ok. Replaced the small circular gaskets between bowl and top of carb. The needle and other 2 gaskets look new. I tried 2 different fuel tanks, one of which I know works. Thanks in advance, John.

 

[angus63]

Re: will only run on choke

If you are getting enough fuel, and it sounds like you verified that, then your getting too much air somehow. Short bursts of ether (starting fluid) while the motor is running all around the intake area (except the carb throats) will tell you where it may be sucking air. Ether is not good for oil lubricated two strokes, so keep to a minimum. A complete carb rebuild with a good soak may prove to help if junk is causing this. Also, did you try a new fuel hose and bulb when using a different tank? Sometimes the hose can be restricted without the bulb flattening.<br />Good luck

 

[wilde1j]

Re: will only run on choke

I would go the complete carb rebuild route (new floats, needles and gaskets). As Angus suggested, soak in carb cleaner, then use compressed air to blow clean. Also, you might check the fuel pump (see shop manual) to make sure outlet pressure is OK. Definitely sounds like a fuel delivery problem. Also, check all tubing from check valves and all other possible crankcase leak possibilities (split half joint, etc.).

 

[tigerking]

Re: will only run on choke

The fuel hose, bulb and tank are new. I have another engine that this setup works fine on. I will soak and rebuild the carbs and replace big fuel lines then check to see if it is sucking air. Where specifically is the intake area? Is that just the area around the carbs? Is there a test to see if any of the fuel hoses are leaking? Where is the half joint on the crankcase? My Seloc manual doesn't show this.

 

[angus63]

Re: will only run on choke

The intake area is the entire region around the carbs. You can cap the fuel lines at the carb fittings and squeeze the bulb real good and give a visual to all of the fuel passages to check for leaks. The block splits in half for access to the internals. A little ether in that region also will indicate a leak if the motor revs up.

 

[jdlloyd_iboat]

Re: will only run on choke

Anyone have any thougts about whether propane gas from a hand torch is OK to use instead of the ether?

 

[wilde1j]

Re: will only run on choke

Either will work, but both prersent a real fire hazard.

 

[tigerking]

Re: will only run on choke

I checked for air leaks using grease. Then decided to pull the carbs a third time. This time I bought the kits and rebuilt them. Funny, they were filthy again, after only running it on the hose once. Noticed top carb bowl was empty (needle sticking). So I cleaned all fuel lines (very dirty), fuel tank (clean)and checked the fuel pump screen. Noticed the fuel pump cover had a big crack in it so installed new fuel pump too. She fires right up. Thanx all.

 

[angus63]

Re: will only run on choke

Aloha and enjoy!!!!!

 

[fireman57]

Re: will only run on choke

Nice touch angus!