Johnson 2003 25hp timing

[Newyota]

Trying to determine why previous owner/owners ground down the starter bracket where timing stopper screw goes thru to achieve more adjustment and be able to lock nut to get proper timing.Flywheel key good.I performed Joe Reeves timing adjustment and I could only achieve proper timing with this extra adjustment also.Rubber stopper good and throttle cam where it contacts good.I am thinking it is related to power pack,but just a guess since I do not see a mechanical reason.Could slow mode defect cause this?Wire is disconnected as of now so it is not grounded.

 

[hgxsilver]

Has the ignition sensor been moved? or can it be adjusted? I believe slow mode grounds a spark limiting the RPM of the engine but that may have just been for older models.

 

[Newyota]

No it was not moved. Whole ignition was changed out by me and bracket was notched out prior to me getting it and motor was running before it had damage done to ignition. Slow mode was just a stab in the dark. Aware that it does limit rpm

 

[Newyota]

No it was not moved. Whole ignition was changed out by me and bracket was notched out prior to me getting it and motor was running before it had damage done to ignition. Slow mode was just a stab in the dark. Aware that it does limit rpm

Bump..Thought I would bump this and see if anyone can help on this issue.Haven’t been able to work on it since last September and with spring on the way wanted to try and figure this out.

 

[440roadrunner]

First thing I'd try to do is to devise way to verify that factory marks are accurate. I'm not familiar with all of these engines, but an example might be my old 73 50hp which has the marks up on top of the flywheel So in it's case, there are actual timing marks that can be referenced.

Can you use a piston stop? this is a "sometimes" adjustable plunger mounted so it can be rigidly locked. Screw the device into no1 making sure that the battery is disconnected, and that the piston is "down" a ways. Gently rotate engine until it stops against the device. Make a temporary, but accurate mark on the flywheel under the TDC reference, or "make" even a temporary index on the block. Now rotate the engine CCW until it again stops. Make a second mark. The true TDC will be halfway in between. You should then be able to reference that against whatever marks are there, to determine their accuracy.

Another possibility. In the older Mopar world, from about 72/ later, Ma used a pickup assembly for breakerless trigger in the distributor. There has been cases where either the coil leads were mis--connected (factory) or the magnet in the device was mis-polarized. This causes the trigger to be offset in time a small amount, and because (in this case) the spark is now happening at the wrong time in relation to rotor position, the rotor no longer alighnes with the cap contacts at the spark even, known nowadays as "rotor phasing."

In any case, even with an outboard ignition, such an odd condition of the pickup/ trigger would MOVE the timing some
Piston stop I made for SB Mopar in the 70's which I still have

Commercial stop available through various places, like Summit Racing. If you get one, be sure you devise a method of locking (nut, etc) the stud rigidly

You read of people suggesting nonsense such as pencils in the plug hole, etc. These methods are not nearly accurate enough, partly because the piston slows down so much as the rod arcs "over the top" of the stroke. You either need a stop such as above, or a dial indicator device. There are methods using a balloon, but ????

 

[Newyota]

Thanks.What you say makes sense.I think if tdc of piston wouldn’t line up with a mark of TDC on flywheel then key would have to be broken on crank and that was ok and flywheel was replaced and electrical under flywheel replaced by me. Not like there is a timing chain or gears on these. Obviously this was an issue from prior owners. I can recheck coil wiring. I guess I was trying to find out if the power pack could be internally damaged/gone bad throwing off timing which is why the timing bracket needed modified?only other thing I can think of. Has great spark.

 

[440roadrunner]

I'm not absolutely sure, but don't think the power pack could do that. It might be worth spending money on the trigger pickup just in case there was something wrong there. Again I'm not intimately familiar with all these, but....is it possible the pickup wires were reversed? Many of these types connectors, the pins/ terminals can be removed, such as to string wiring through "a hole."

 

[Newyota]

Trigger was replaced as stated when replacing ignition parts under flywheel.