Question on CDI/Ignition Coil Testing for 87 dt 9.9

rdhj

Petty Officer 2nd Class
Joined
Sep 29, 2015
Messages
102
I am still having issues with my motor coughing at mid throttle and high throttle too. Also, seems to not want to decide weather it wants to idle without stalling or not. I am sure my carb is clean and she is getting fuel. so, I started to suspect the ignition. As far as I can tell using the manual, the timing is fine. I got 250 ohms for resistance on the charging coil, which is in spec, but when I check the secondary resistance between the two spark plug ends, I get nothing.

Question is if the coil is bad and showing no resistance, should I still be able to start and run the motor?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
sounds to me that you are talking about a lean sneeze not a spark problem.
probably testing with the proper equipment will tell you if the charge coils, ignition coils and all other inputs and outputs of CDI are in spec.

does your manual give you specs for the way you are testing the plug wires and ignition coil?
 

rdhj

Petty Officer 2nd Class
Joined
Sep 29, 2015
Messages
102
sounds to me that you are talking about a lean sneeze not a spark problem.
probably testing with the proper equipment will tell you if the charge coils, ignition coils and all other inputs and outputs of CDI are in spec.

does your manual give you specs for the way you are testing the plug wires and ignition coil?

yes, i followed the procedure in the repair manual which has the specs in the tables. last night when it was doing it, i turned the adjustment screw out a little more for more fuel, but that didn't help any.
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
Your motor starts and runs, but stalls at idle,the odds are high it's fuel delivery
You need to remove your carb from your motor, remove all the parts, and clean them, replace any gaskets and parts you break.It's on you tube watch all the carb rebuilding/cleaning videos.
If you have a welch plug remove it lots of small hole under it.for idling
Replace on motor fuel filter
Clean your spark plugs.till clean and shiny no black carbon anywhere.
New gas.
I don't think you have error codes on this motor.
.
 
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rdhj

Petty Officer 2nd Class
Joined
Sep 29, 2015
Messages
102
Your motor starts and runs, but stalls at idle,the odds are high it's fuel delivery
You need to remove your carb from your motor, remove all the parts, and clean them, replace any gaskets and parts you break.It's on you tube watch all the carb rebuilding/cleaning videos.
If you have a welch plug remove it lots of small hole under it.for idling
Replace on motor fuel filter
Clean your spark plugs.till clean and shiny no black carbon anywhere.
New gas.
I don't think you have error codes on this motor.
.

It's not fuel delivery or float bowl height. I had cleaned the carb a bunch of times and check the float height last week.It accelerates fine and runs, but coughs when you get to mid range and high speed like the plug skips a beat every 5 seconds. I found this online that may be explaining what is happening

If infinite (no continuity), an internal open circuit exists. Replace the coil. If infinite and the engine runs, your problem is an internal break of the high tension lead, a poor attachment of the spark plug terminal or improper mating of the high tension lead to the coil.

I just want to make sure this is the bad part before i drop $117 on a singapore replacement part.
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
Test first, every electrical/ignition part first with a multi meter or DVI before you buy a "Singapore replacement part
 

rdhj

Petty Officer 2nd Class
Joined
Sep 29, 2015
Messages
102
Test first, every electrical/ignition part first with a multi meter or DVI before you buy a "Singapore replacement part

I did test the secondary residence with my multimeter and got no reading...guessing there is a short in the ignition coil
 
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