Backfiring help needed

[mercedes84black]

I have a Johnson 175hp (model 175TL79R) backfiring thru prop. Flywheel key was sheared so I installed a new one, torqued to 105psi, tdc now lined up, sprayed a little starter fluid, still backfiring thru prop (exhaust). Coils and wire next to plugs so can't go wrong there. Am I missing something

 

[mstahl1171]

Are you sure the leads from the power pack to the coils are in the correct order?

 

[mercedes84black]

Not sure< I bought the used motor as is after compression testing 90psi all cylinders. Not sure which colors go to which coil (yellow w/red stripe etc.)

 

[mercedes84black]

doesn't start just backfiring

 

[rick s.]

sounds to me like you have the spark plug wiring messed up.

 

[mstahl1171]

go to this link....see page 45. http://www.cdielectronics.com/wp-content/uploads/2013/02/CDI%20Troubleshooting%20Guide%20-%202012.pdf test all the power packs, stator....etc. Are you sure the key has not broken and the flywheel has slipped out if timing?

Do you have a service manual?

Others with way more experience than me will chime in soon.


Mark

 

[mstahl1171]

Also check out Max Rules site http://maxrules.com/JOwireindex.html he does not have your exact year...but the early 80's models should be similar. Someone here may have your wiring diagram

 

[joereeves]

The torque is wrong!

The flywheel nut torque on a V6 is 145 foot pounds.... and the key must absolutely be the proper 307480, not some key from a hardware store. Also, the key must be installed so that the straight edge is vertical with the engine... NOT... aligned with the crankshaft taper.

Make sure the flywheel and crankshaft tapers are clean and free of defects from being spun!

 

[kimcrwbr1]

blue is 1 and 2 and green is 5 and 6

 

[mercedes84black]

Everything is now correct. The engine is now trying to start. Seems like it's going to start but just not quite catching

 

[mercedes84black]

Looks like excess gas coming out the front of bottom carb

 

[mercedes84black]

also it's on a stand and the engine is kind oft tilting forward rather than sitting even, could that be why it's not quite starting

 

[kimcrwbr1]

Tap on the side of the carb with a wrench will sometimes get the float working again. You mentioned starting fluid is a no no it has no oil in it and can cause damage internally. Pull the plugs and see if they are wet? If so see if they burn with a lighter. Were the wires crossed up?

 

[joereeves]

Not sure< I bought the used motor as is after compression testing 90psi all cylinders. Not sure which colors go to which coil (yellow w/red stripe etc.)

Top Cyls === Orange/Blue stripe
Center Cyls = Orange (No stripe)
Bottom Cyls = Orange/Green stripe

 

[mercedes84black]

It's acting like it wants to start but there's still a backfire from the exhaust. Today I bought a spark tester. 1-3-5 was sparking. On the other head 2-4 wasn't doing anything 6 was sparking. Any ideas

 

[kimcrwbr1]

Swap the coils 1-3 with 2-4 and see if it follows the coils? if it stays the same your issue is upstream either powerpack or trigger. swap the powerpacks and see if it follows the pack.