Continuing saga of the non-running 48 special

Genonbamagirl

Petty Officer 2nd Class
Joined
Dec 9, 2008
Messages
134
Got it running and now it pops (backfires) at and near idle. It runs okay (not perfect but close) at higher rpms.

1978 Starcraft Aluminum hull 16' with walk thru and 1995 48 spl. Was a PA marine police unit for a few years, fishing boat in PA for ten or so years, a taveling fishing boat owned by a retired marine friend of mine who just puttered around here and there for 5 or so years then owned by a retired Navy buddy who neglected it. It sat for at least the last two years.

Motor didn't run at all on Monday, boat has rotted wood in every single panel that I have inspected so far with the exception of the deck and it was replaced a few years back with too thin plywood so it feels a lot like a dojo floor - nice and springy.

Poured out the bad gas and put in fresh mix and got it to crank but the alarm sounded all the time and it didn't pump water at all. Cleared the gunk from the impeller, disconnected the faulty alarm horn and ran it for several hours on Tuesday. Have not touched the carbs, have replaced the plugs (no difference) and have not touched anything else on the motor. It has good compression on upper and lower cylinder and both are running (using the touch the cylinder and burn your hand method - okay - not really burned hand because not hot enough but both seem to be equally warm).

Also have the tilt assist unit inside the boat and was told that it was bad. It looks like new but I can't move the cylinder by hand. Can these be rebuilt? The cable end is broken so maybe that is the issue - can new cable ends be obtained?

Ideas? Suggestions?
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Continuing saga of the non-running 48 special

The carb's need to be stripped and cleaned.
 

Genonbamagirl

Petty Officer 2nd Class
Joined
Dec 9, 2008
Messages
134
Re: Continuing saga of the non-running 48 special

The carb's need to be stripped and cleaned.

Crap!!! I knew it and didn't want to admit it.

Pull out all the parts and clean them with spray cleaner or vat them? I assume the pilot jets will have some sort of little tiny holes that are clogged causing a lack of mix at idle? Are there two jets in these that work like a motorcycle carb - a pilot (or idle) jet and a standard jet?
 
D

DJ

Guest
Re: Continuing saga of the non-running 48 special

Crap!!! I knew it and didn't want to admit it.

Pull out all the parts and clean them with spray cleaner or vat them? I assume the pilot jets will have some sort of little tiny holes that are clogged causing a lack of mix at idle? Are there two jets in these that work like a motorcycle carb - a pilot (or idle) jet and a standard jet?

You get the picture. On the "two lung" OMC's a "pop" or "sneeze" means a lean mixture. Don't run it like that, you'll score a cylinder.

Yes, disassemble both carbs and clean every orifice with compressed air.
 

Genonbamagirl

Petty Officer 2nd Class
Joined
Dec 9, 2008
Messages
134
Re: Continuing saga of the non-running 48 special

I'll report back in tomorrow.


STUPID CARBS............................

What about the trim (sort of) unit?
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: Continuing saga of the non-running 48 special

Remove and dismantle the carbs. Remove rubber components and gaskets if applicable. Purchase a 1gal can kit of Gunk brand carb and parts cleaner. Follow the instructions. Your carbs will be clean. Use Stabil in all your fuel to minimize the necessity to do all this again.
A manual on your motor is a good investment.
 
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