PLEASE HELP! 74 sportster fuel problems

[jtjt]

I have a 74 25hp sportster that wont suck fuel, ive put a new pump on it and tried just about everything, new plugs and spark is awesome, removed carb and is super clean, starts first pull if its got fuel. removed pump from engine
and ran it shortly to check for pulse and did not seem very strong? is this normal? could it be a bad cyl or reed? Im also using a mystery tank, do i need a different fuel pick up for different engines/brands? im a good auto mechanic but im a little green on outboards but very familliar with 2 stroke dirt bikes so im open to all suggestions and familliar with typical lingo just need a little help along the way. PLEASE HELP THANK YOU!

 

[andrewddrennon]

Re: PLEASE HELP! 74 sportster fuel problems

If by pulse you mean crankcase pressure and vacumm?? that probably isnt a problem if it runs ok for a bit. Not sure how your feeding it fuel without a fuel pump on it?? You may already know but.....dont use starting fluid......that will ruin it. Use mercury power tune or gas/oil premix in a squirt bottle. Fuel induction wouldnt be right if you had a bad crankcase or cylinder and in most cases it wouldnt start right up. Does the motor run at all by itself? Also make sure the bulb is firm. Try and find a known good gas tank and fuel line/bulb.
If you do that and still have a problem pull the outlet hose from the fuel pump off the carb, crank the engine over, you should have a steady stream of gas coming out while cranking. You would have to put the fuel pump back on to do that test.

 

[jtjt]

Re: PLEASE HELP! 74 sportster fuel problems

Thanks for replying much appreciated! When i pulled the fuel pump off i left the lines hooked up so i could still fill the float bowl by pumping the bulb but i only let it run for a few seconds, i put my thumb over the hole and the pulse didnt seem very strong. the only way i can get it to run is to put the tank higher than the motor and it will run all day long cause it siphons out but as soon as i put it down low it wont pull fuel up unless i pump the bulb, it will idle very low but as soon as you give it any rpm it just sucks dry, hopefully my dad is coming over with his compression tester today and all is well. I dont want to give up yet!

 

[F_R]

Re: PLEASE HELP! 74 sportster fuel problems

You got two threads going. Read the other one, and end this one.

 

[jtjt]

Re: PLEASE HELP! 74 sportster fuel problems

ya your right i do have two going, im hard up what can i say?