misfire

bolldom

Recruit
Joined
Mar 21, 2022
Messages
2
i have a evinrude 9.9 the motor starts and runs on one cylinder after running about 5 minutes the other cylinder fires and boat takes off. changed plugs no difference. can someone suggest troubleshooting procedure?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,821
We start with asking for a model # as not all are the same.-----And sometimes a 9.5 is called a 9.9 or 10 HP !
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,821
A 1994 model.-----Use a timing light to see which cylinder is not firing at start up.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,796
a recent case was related to overheating in a coil module

oddly in your case it seems to need extra heat to start working....

recheck all connections and grounding associated with coils.
heat may be expanding & closing a broken or oxydized connection .
 
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