Start Trouble

le pirate

Recruit
Joined
Sep 19, 2009
Messages
5
Hello All,

1979 Holiday 18' Mercruiser 120 4 cyl
Rochester 2 jet carb with auto choke.

I am nearing the end of my boat reno. The current status of the boat is semi running, if thats possible. Prior to taking everything apart it was running. I did nothing to the engine besides change the oil.

The current problem- the engine turns over and fires, it has a somewhat rhythmic sequence of firing but nothing i would consider close to starting. the coil has been tested and is proper. Points condenser rotor and distributer cap all replaced. I tested each plug wire with a light tester. Each lit the tester, however the plug wire for cyl. 1 is slightly broken where it connects to the distributer, although it still sparks. On the fuel end the fuel pump is functioning, with a new fuel filter and 5 gallons of new gas. This leads me to believe it is the Carb.

I have cleaned the carb from the outside as best as possible. dissasembled auto choke and cleaned. Removed mixture screws, cleaned and replaced to og. position.

When i turn the engine over i get intermittent combustion. quite often the engine will backfire out the carb. full throttle to no throttle has no major effect on the performance. starting fluid will combust but no major help.

I havent tested compression as i have no tester. But it was running prior, and the block hasnt been touched.

Any suggestions to get it going would be great.
Thank you much, zak strong

below is pic of carb. hope it helps.
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,333
Re: Start Trouble

install new plug wires and plugs

did you set dwell??

are you pumping the throttle and verifying fuel is getting into the carb throats??

perhaps the timing is off, have you checked it with a helper cranking the engine??
 

Lyle29464

Lieutenant
Joined
Mar 10, 2009
Messages
1,261
Re: Start Trouble

I would can the starter fluid. I have used it on occasion. Mainly working on an overboard. I just mist a split second shot near the carb, But anyway, If you have the flame arrester off ,the choke propped open and have given it a shot of gas or what ever down the carb it should run good for a second or 2. If not I think you can rule out gas. I would disconnect all the wires on the - side of the coil and hook back up the one to the distributor. If that does not do it I would run a wire from the + on the battery to the + on the coil. and try that.

Lyle
 
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