How to set timing on 175hp 1986

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sqshieldman

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The engine backfires when attempting to start it, I would the timing be set prior to starting? I have a johnson 175hp year 1986
 
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boobie

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Re: How to set timing on 175hp 1986

Is the flywheel key sheared ?? Plug wires crossed ??
 
Joe Reeves

Joe Reeves

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Re: How to set timing on 175hp 1986

If that engine is indeed "Backfiring", that is, it is firing loudly out the exhaust port(s).... then "Boobie's" reply is the only cause that I can think of... UNLESS... you have adjusted the full spark advance stop screw way out of its proper setting and are trying to start the engine with the spark advance set wide open.

Have you actually removed the flywheel to check the flywheel key? Flywheel nut must be torqued to 145 foot pounds to avoid shearing.

Between the last time this engine ran properly and encountering this backfiring scenario.... has any work been performed on the engine, then this problem popped up?
 
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emdsapmgr

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Re: How to set timing on 175hp 1986

All above comment are good. That engine has the dual power packs. While the plugwires may not appear crossed, the special color-coded orange wires from the power packs to the coils could be crossed. (feeding the wrong coil.) That will also cause backfire.
 
Joe Reeves

Joe Reeves

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Re: How to set timing on 175hp 1986

emdsapmgr said:
All above comment are good. That engine has the dual power packs. While the plugwires may not appear crossed, the special color-coded orange wires from the power packs to the coils could be crossed. (feeding the wrong coil.) That will also cause backfire.
Click to expand...

Yep... I was waiting for the poster to come back online as my next question/comment was going to be about the location of the Orange/Blue (top), Orange (center), and Orange/Green (bottom) leads to the coils.
 
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sqshieldman

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Re: How to set timing on 175hp 1986

Joe Reeves said:
Yep... I was waiting for the poster to come back online as my next question/comment was going to be about the location of the Orange/Blue (top), Orange (center), and Orange/Green (bottom) leads to the coils.
Click to expand...

Thanks everyone for help and input I really appreciate it. I checked the wiring it is correct, I am not able to pull the fly well off becasue the thread on the three bolt holes is crossed. I am waiting on a repair manuals to reference. A little history I purchased the motor recently used I was able to to start it at first but it did back fire at that time, I cleaned out the carbs and replaced all the fuel lines since there were some cracks in them and replaced a leaking manual choke valve and then after doing this I tried to start motor and it still back fires but not as bad, motor does crack over but will not start.
 
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emdsapmgr

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Re: How to set timing on 175hp 1986

As you prepare to cold start the engine: you'll choke the engine and move the idle lever up for fast idle-while cranking. After cranking for 10 seconds, pull a couple of spark plugs. Do they appear to be wet or dry?
 
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emdsapmgr

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Re: How to set timing on 175hp 1986

Wet plugs indicate they are getting fuel. What did you check to make sure the flywheel key was not sheared-since you did not pull the flywheel? Did you check the timing?
 
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sqshieldman

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Re: How to set timing on 175hp 1986

I originally did a visual inspection of the fly wheel, so this morning I did pull the flywheel off and the key is sheared I am replacing it today, however 3 of the 6 magnets have come loose, what would be the best way to re attach? Thank you everyone who has posted helping me to try and get this motor back up and running.
 
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emdsapmgr

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Re: How to set timing on 175hp 1986

The magnet problem may be why the key sheared. Your 175 must have the high capacity 35 amp alternator with the vented flywheel. Those magnets tend to loosen with age. You can re-glue those magnets. Bombardier makes a flywheel magnet glue kit for just that exact engine. See you dealer and ask for part number: 431929. Probably under $ 10. If you want new magnets with the glue kit, ask for part number: 584304. Probably under $25.
 
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boobie

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Re: How to set timing on 175hp 1986

Read post # 2 again..............Follow the instructions on glueing the magnets back in. Make sure you get them in the right direction, have everything clean and use the proper spacer bolt. I think I used a 7/16" bolt. When done, torque the flywheel nut to 145 ft lbs.
 
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