rebuilt 15 hp.. help!

[SCduckhunter]

Rebuilt my 85 j15rcob yesterday..followed all torque specs and everything...had my factory manuel as well as.leeroys ramblings on hand...it went together fairly smooth..when we went to fire it up it well to be honest didnt....didnt do a durn thing...it has compression and fire and fuel as far as we can tell..it back fired a few times.. i put new plugs in it..the correct ones...it seems to me like its timing related or something simple...where should i start?? Thanks yall

 

[kbait]

Re: rebuilt 15 hp.. help!

Spark plug wires mixed up? If not, try switching the leads to the coils from the powerpack.. if they were reversed, it'd act just like mixing up the plug wires and act exactly as you describe.


Good luck!

 

[SCduckhunter]

Re: rebuilt 15 hp.. help!

Actually already.tried that...switched plug wires..no crank...switched em back and switched power pack leads..no change...it spins over great..just wont fire...can it have anythingto do with the throttle and statorplates being off by a touch or somethung? It just seems like timings..on a car id check timing this im not sure...

 

[Will Bark]

Re: rebuilt 15 hp.. help!

Look for a sheared flywheel key; that will affect the timing as you describe. Good luck

 

[AlTn]

Re: rebuilt 15 hp.. help!

if it ran before the rebuild and you haven't altered the carb or ignition, check your link and sync first, then put some fuel directly into each cylinder and try to fire it up.

 

[SCduckhunter]

Re: rebuilt 15 hp.. help!

Replaced flywheel key brand new omc part that stupid.little thing is 8$...whats a link and sync that maybe my issue...i took.everything off of motor and had cylinders honed so i very well may have misaligned something during install

 

[raczekp1]

Re: rebuilt 15 hp.. help!

what about gaskets at the mainfold intake. there are 2 gaskets.
if instaled in wrong way, leaf valve cant open

i think problem is in carb

 

[AlTn]

Re: rebuilt 15 hp.. help!

go to leeroy's ramblings and read his writings on maintenance and repair of the 9.9/15 hp. series..it'll cover the link and sync procedure as well as many other things

 

[OptsyEagle]

Re: rebuilt 15 hp.. help!

Rebuilt my 85 ..it has compression and fire and fuel as far as we can tell..it back fired a few times..

How did you test that it has compression, fire and fuel?

By the way, what did you rebuild.

Outboards rarely backfire, especially if the exhaust is not already screaming hot. The only way it can back fire, when the exhaust cavity is cold is if the spark is firing way past top dead center. When you reversed the spark plug that each coil boot was going to, did you also change the other coil wires, before you checked if it fixed anything. It really sounds like your spark plug wires are going to the wrong cylinder ... or your flywheel key is sheered.

 

[SCduckhunter]

Re: rebuilt 15 hp.. help!

I had the block checked over and cylinders honed reringed the pistons...replaced all the bearings and needle bearings and crank seals replaced all gaskets basically redid the entire guts... the power pack and coils have about 1 hour on them prior to rebuild.. put it together and when trying to crank it a few hours( after dinnerreally) after rebuild we couldnt get it to fire.. the flywheel woodruff key was put in brand new as part of the rebuild.. i havent had time to look into it the last few days..the " backfire" was actually some carb cleaner that when checking spark ignited apparently while the plug was out of cylinder..i thought after previous problems with this.motor and how to diagnosis issue to check to see if the coils were incorrectly wired..i first just swapped plug wires.on the plugs..i then.swapped the powerpack to coil leads..i then reswapped plug wires...nothing helped it fire... i will defiantly check.flywheel key as soon as i can.. i hope its something just that easy..

 

[OptsyEagle]

Re: rebuilt 15 hp.. help!

OK, so if there was no spark plug in the cylinders when it backfired, then forget my spark plug boot reversal and flywheel key sheering suggestions. It could be them but it was the backfire that led me to the suggestion and what you seem to describe is not the normal outboard backfire.

Next question, and you have eluded to it, have you put some premix fuel directly into the carb throat and/or spark plug holes and tried to see if you get a pop out of it? and did it pop?

Someone mentioned about link and sync. Is your carb sync'd up with the timing plate. When you turn the throttle arm a throttle cam comes along and starts pushing on the roller on your carburetor to open the butterfly and give more gas. There should be an arrow, line or mark on that cam. When the roller just touches the cam, that mark should be in the middle of the roller. Is it?

Lastly, do you have the throttle turned fully up to the neutral stop when trying to start the motor?

Is your choke working properly?