Logo
FULL SITE MENU

Distributor cap?

A

arunas

New member
Hi Guys
Have a Mercury 1973.
500 50 HP.
Not working 3th and 4th cylinders.Spar plugs and wires OK.
I'm almost sure that it is the distributor cap's fault,but i hope that maybe it is not.
Does any of you have any ideas?
Do you have any suggestions where i could find a cap replacement?

Thank's
 
333-3143 333-3142A3 are the part numbers are you willing to sell your first born? Be real careful as all ignition parts are real expensive if you can find them.
 
Last edited:
How are you checking spark? Use a open air spark gap tester it should jump a gap of at least 3/8 inch gap on all four plug wires brite blue snap.
 
The wires may have backed out of the cap. (A screw skewers the wires to hold them in place.) If so, there's an air gap inside the cap that the amps can't jump.

Grab each wire and give it a strong tug. If they move, there's the problem.

Jeff
 
Thank's Guys.
The spark from 3-4 wires is so small and variable.I compare with 1-2 cylinders.
I tried to check spark without plug,straith from wires.
The wires ends is connecting properly
The cap inside is clear and have not sooty at points where can be damage.
I changed wires. ...Same problem.And I still cant find new cap online.:confused:
 
Last edited:
If wires from 1-2 cylinders not working on 3-4 and 3-4 working on 1-2 ...it's elementary.
Thank's for the address.I'll check immediately.
 
It is cheaper to buy the gasket set, welsh plug, needle/seat and float there is no need to remove the throttle butterfly but do remove the welsh plug and use the proper screwdrivers for the jet and emulsion tubes. soak them good in carb cleaner and blast the circuits with high pressure water and blow them dry with air. Rod out all the little holes in the emulsion tubes with fine wire and use a soft copper wire on the jets. Make sure the float seat is nice and tight with a new copper washer inside and do not put finger pressure on the float needle to adjust it, pull it apart and bent it then check it with very little pressure on the lever.
http://www.marineengine.com/parts/m...thru-4140999-usa/carburetor-assembly-complete
 
Last edited:
Back
Top