resurection in progress .....HELP!

[dpty22]

i have a 1975 johnson 85hp 4cyl. I have changed the rectifier because the wires were melted. today i hooked it up to a battery and turned the key! starter works. crank spins and a copression check shows 100 on the cyl on the left. and 105 on the ones on the right. then i held the plug in the wire and grounded it on the head and no spark. changed plugs and no spark. put a test light on the screw that is identified as coil 1, 2, 3, 4, (on the rectangular box between top cylinders on back side of motor) and no light while turning it over. how should i be checking for spark? also i had to replace the small buss fuse that is conected to the recifier and blew it again. the third one still in tact. the ones i bought were 5 amp. any suggestions of what to do next is greatly appreciated. (shop manual is on order, the one i had got wet before the motor did)

 

[racerone]

Re: resurection in progress .....HELP!

Takes a 20 amp fuse !!

 

[dpty22]

Re: resurection in progress .....HELP!

i will get 20's i think the hardware only goes as high at 10 in the short ones but i will bet that it is better than the small bolt that the previous owner had in it.

 

[Daviet]

Re: resurection in progress .....HELP!

If you go to the CDI website and look up your engine, they will have a troubleshooting guide to help you with your spark problem.

 

[emdsapmgr]

Re: resurection in progress .....HELP!

That engine has to crank at least 250 rpm's in order to fire the ignition. The CDI website is excellent. You've got four ignition components, 4 spark plug coils, a stator, timer base and a power pack. Doubtful that 4 coils go bad at once. Look at the other 3 first.

 

[dpty22]

Re: resurection in progress .....HELP!

ok so the engine has to crank at 250 rpm but, i have it hooked up to the cranking battery and the controls like it would be on the boat. is that not going to be at least 250 rpm? (not to be an *** but just wondering). i looked up CDI and still looking through the results. quite confusing.

 

[emdsapmgr]

Re: resurection in progress .....HELP!

You may want to get an original factory manual that is specific to your engine-they are very helpful. Moreso than the Clymer or Seloc manuals. Check this website: outboardbooks.com

 

[racerone]

Re: resurection in progress .....HELP!

If the starter is not in good condition it may not crank fast enough !

 

[dpty22]

Re: resurection in progress .....HELP!

i thought i had a great idea....I marked the flywheel with an orange marker and cranked the engine t count how many times the mark went around in 5 seconds and multiply by 12. well after taking apart, and cleaning the starter, i cranked it and couldnt even see the orange mark. what is the best way to check rpm while cranking? I was also thinking that if i couldnt see the mark on the flywheel that it was spinning faster than 250 rpm?

 

[Bosunsmate]

Re: resurection in progress .....HELP!

easiest way is to post a video.
if you think you are capable of seeing the mark going around it prob isnt going anywhere near 250rpm

 

[emdsapmgr]

Re: resurection in progress .....HELP!

There's an easy way to check for spark on a non-running engine. Use an inductive timing light, connected to one/each of the spark plug wires. Crank the engine. The flashes from the head of the timing light, (gun) will show you the spark activity. You will be able to see misfires, no fires and weak firing. Compare the spark from all 4 plugwires. Your compression is somewhat low for that engine. Should run, but 125 lbs on each cyl is more typical for that year/model. Maybe try another compression gauge. You may want to have a look down the spark plug hole and see what the piston crowns and cyl walls look like.