need a little help
 

hello all, im new to the boating world. i just picked up a 81 sea ray 305. i/o i know its old but its in real good shape. i have put in a new starter,plugs,wires,cap,rotor,rebuilt thecarb,new coil,fule/water sep. i have gone threw this motor real good. i have been working on cars for a long time. but boats are new to me. ok now to my problem. it will turn over and fire and run for about 30 sec. if i keep giving it a little gas i can keep it running for a few min. but wont idle its almost like its running out of gas. it also did this befor i rebuilt the carb.i have played around with air fule mixture with no real changes. im kinda stuck. any one have any ideas?

Do you have fresh fuel in the tank?

yes. drained it. ran the same. i also just tryed to run it off a gas can just to check.

Try turning up the idle screw until it stays running then adjust your idle mixture screws.If you can get them to a point where it runs smoother and faster then start turning down the idle screw.I'm assuming you have the timing set correctly.It could also possibly need a fuel pump.

That helps now you know it is the engine, Try to find a way to test the fuel pump pressure. Most carb engines are round 8 [psi]

i will put a fule pressure gauge on it today. but if that was bad would i be able to keep it running for a few min? i know it will run for a little with the fule in the bowl.

1981 has a points dist. ,you didn't say anything about that. New points and cond. dwell @ 30* timing @ 8btdc. That being said when it is running is there good throttle response?

yes i have done all that. cond...points. all set at factory specs. the response is not that good.

bluez,have you tried a remote fuel can hooked to your fuel pump? There is also a check valve in the main fuel line between the pump and the tank that has been known to go bad before.Do you have a quadrajet on it??

yes it has a 4 b quadrajunk on it. i have tryed a remote fuel can.

Well then, if your eng. is mech. alright and the ing. is all set and double checked it has to be the pump or the carb. Quadrajets (I myself like them most don't) can be tricky. Make sure all the passages are clear is one of the main things,air or even tag wire.I have had a few apart more than once before they were right and i have done lots &lots.(new carb kit&float)Were you keeping it running with fuel directly thru the throat or filling the float bowl thru bowl vent tude on top??

Hey bluez, forgot to ask whats a 305 anyway?????

Small block chevy.

If it has points you also have a ballast resistor. Usually mounted to the front of the coil. This resistor drops voltage to the points at idle so the points don't get burned. They are cheap, you might consider changing that and I would look closely at the points again. Burnt points act like you describe.

If you find out the problem is in the points I would get rid of them. I have an 80 Sea Ray DA with a 350 in it and ditched the points for a electronic ignition kit from petronix. You can find them for 65.00 online, they fit under the distributor cap and make your engine run a lot better overall.

I agree that your problem sounds fuel related. Id say fuel pump or carb issue. If you can get her to stay running by giving it gas I would start there and work backward. Check to make sure your getting good strong spark to rule out the points.

Billy

thanks for all the help. sat im going to dig into it again. i will let you know what the out come is.

I would check for a vacuum leak. Make sure the carb is sealed well to the manifold, check that there are no caps missing on the carb fittings used for vacuum to other things that may not be used on a boat like power brakes. Not so sure about a qudrajet, but Hollys have a 1/4" or so tube on back of the base plate for vacuum accessories. Make sure it's pluged.