165hp i/o wont start - no spark

[seabass1000]

Me and a friend are trying to get his boat started for the summer and are having no luck. It is a 20' 1969 with a 165hp mercruiser i/o. It turns over fine but wont start. Getting no spark at plugs. Replaced the coil, condenser and cap, re-set the points in the cap. Put in new fuel(boat has sat for apro. 14 months), checked the coil with a ohmeter and got 12volts, fuses are all fine. We cleaned off all the wires becuase they had some corrosion on them. We are out of ideas, any help would be greatly appreciated. thanks.

 

[tommays]

Re: 165hp i/o wont start - no spark

try checking the coil by unhooking the wires and useing the meter to check how many ohms it is showing ,dont no what it should be but this will let you know if the coil is open <br />also 12 volts sounds high there is usally some type of resistor that would give you less than that with out the right one you will burn up ingition parts<br /><br />tommays

 

[hoot]

Re: 165hp i/o wont start - no spark

coil could be grounded thru the kill switch or shift interupter switch. how did you read 12 volts? with igniton switch in the on position, about 7 is what you are looking for at + terminal if you have an external resistor (wire or ballast). maybe you should have replaced the points also. do you have a point file to clean the contacts?

 

[rattana]

Re: 165hp i/o wont start - no spark

An easy way to see if the primary circuit is working is connect a 12VDC light between positive and negative on the coil. Crank your engine over, the 12VDC light should flash as the points are opening and closing. Let us know what you find.

 

[MrBill]

Re: 165hp i/o wont start - no spark

MAke sure you are getting continuity across the points. You mention re-setting the points, but didn't say if they were new. Often points look very good, but there may not be continuity across them...an easy check...rotate engine (distributor shaft) to close points and check continuity. If weak contact or no contiuity, replace.