Stumped - Won't turn over

[brodie123]

Mercruiser 165 inline 6
fire order: 1-5-3-6-2-4 --- checked
compression: good and equal on all 6
Gas: fresh
spark: tested on all 6
plugs: gaps checked
wires: 2 yrs old
Timing checked: 6 degress BTDC
Ignition: MSD 6A + MSD coil --- power checked

I de-winterized the boat and she started up like a dream. I replaced the old distributor (rough shape) with a MSD 8515 - ran well.

I changed the springs to the recommended for the time curve chart, changed the limiter to 25 degrees.

Now all she will do is back fire. I can't get her to turn over at all. I thought maybe I flooded her so I pulled the plugs and opened up the carb to let her dry-out overnight. I leaned the carb out completely. When I turn her over, I get zilch for firing. If I add a little gas - nothing. A lilltle more gas and she back fires through the carb.

Please Help !!!

 

[Bondo]

Re: Stumped - Won't turn over

Now all she will do is back fire. I can't get her to turn over at all. I thought maybe I flooded her so I pulled the plugs and opened up the carb to let her dry-out overnight. I leaned the carb out completely. When I turn her over, I get zilch for firing. If I add a little gas - nothing. A lilltle more gas and she back fires through the carb.

Ayuh,.... Turnin' Over, is what it's doin' on the starter,.... Firin', runnin', or startin' is what yer Not gettin'....
Just semantics, but We've all gotta be talkin' the same language...

It sounds like the ignition is off,... Way off,.... plug wires run wrong, cap on crooked, distributer out 180?,..??

If it Runs, 'n backfires, I would look to a Lean condition...

When ya pulled the plugs out to dry it out, were they Wet,..??

 

[stonyloam]

Re: Stumped - Won't turn over

If it is backfiring through the carb, it must be firing the plugs on the intake stroke while the valve is still open, so it sounds to me like your timing is WAY advanced. Did you pull the distributor to make the changes, maybe got it back in 180 degrees out. Bump it to tdc compression and see where the rotor is pointing, should be right at #1 plug wire.

 

[brodie123]

Re: Stumped - Won't turn over

ya - sorry, not firing is what I meant.

The only time she backfires is if I spray a liberal amount of fuel with my gas spray bottle. Otherwise, she doesn't back fire.

I did pull the dist. to change the limiter. (dist. needs to be upside down). I set the crank to line up TDC (timing mark to zero). re-installing, the rotor rotated 180 due to alignment on oil pump. I re-did the wiring to make sure proper order. With all 6 plugs out and my spark test on plug 1, I cranked the motor and set the time to 6 degrees. I've done this 3 times now - getting the rotor to rotate 180 again.

The plugs had a little bit of gas, but not excessive (I would say). Not dripping by any means - but "damp".

Are you saying I'm running too lean? Or not lean enough? I leaned the carb incase I was running too rich. I then let her turn over quite a bit, add some gas manually, when I gave too much "POOF". The only time she ever did that to me before was when the carb float was stuck open a few years back - I had the carb re-built.

I set the crank to TDC and the rotor is pointed right to cylinder wire 1. I made sure the cap is on correctly.

I am totally stumped on this one!

 

[Don S]

Re: Stumped - Won't turn over

I set the crank to TDC and the rotor is pointed right to cylinder wire 1. I made sure the cap is on correctly.

Make sure you are on #1 TDC on the compression stroke when the rotor is pointing at the #1 plug wire.It sounds like you are on the exhaust stroke.

 

[brodie123]

Re: Stumped - Won't turn over

ya know I just came to that exact conclusion. Can you post the proper procedure for ensuring I am on compression stroke as I am obviously doing it wrong.

 

[Don S]

Re: Stumped - Won't turn over

http://forums.iboats.com/showthread.php?t=427081

 

[brodie123]

Re: Stumped - Won't turn over

When you don't do this all the time - and you don't read your notes - you can make stupid mistakes.

She's purring like a kitten again.

Thank you SO much guys!!