Timing 3-cylinder 65hp

[jbjennings]

Just wanted a double check from the pros:

1. Got piston number one at top dead center by using screwdriver in spark plug hole and feeling for highest point of piston travel, being extremely careful that it was at the highest point.
2. made timing pointer with wire and marked on block behind it for reference points to keep line of sight proper.
3. Set up timing light on #1 wire. Timing was about 4 degrees advanced at idle--flywheel said it should be 2, I didn't make a change since it idled at the right speed and was smooth. I still may take it down to 2 degrees on the idle stop screw and reset the idle jet.
4. I cranked the motor at idle and rotated the distributor by hand until the shoulder of the lever touched the spark stop. It was far, far too advanced.
5. I reset the spark stop screw until it was perfect at 23 degrees which was what the engine said it should be at on the exhaust cover.

I haven't had a chance to run it (just got finished) yet. I noticed that the spark stop screw was really screwed in pretty far, and that the lever didn't travel very far (maybe a half inch or so at the most) until the shoulder of the lever hit the stop screw. I thought it would need to travel farther than that, but 23 degrees advance is 23 degrees so I left it at that. I'd say the phillips head end of the spark stop screw only stood out about a half inch behind the lock nut. I know the throttle will keep going after the spark stop hits and that it hits full advance at about 3/4 throttle or in this case maybe sooner....

Does this sound correct to you guys and is my procedure o.k? ALso, what is the punch mark at 27 degrees for on the flyhweel timing indicator sticker? Are there some situations that call for 27 degrees advance?
Thanks ahead,
JBJ

 

[Faztbullet]

Re: Timing 3-cylinder 65hp

The screwdriver method is not accurate so use a dial indicator instead and you could still be several degrees off

 

[Fishcake42]

Re: Timing 3-cylinder 65hp

Hi, not a "pro" with regards to outboard, but have been through this procedure a few times. Screwdriver method is good for generalising where TDC is but, not quite accurate enough. You also have to account for the hang-time (rotation has continued before and after TDC but the piston has topped out and has no movement. My manual referenced this.

What I can add is when I went through this I found initially the same observation that spark stop lever was not moving a great deal. Upon closer inspection it turned out the carb cluster pin had been poorly installed. When I corrected this, and completed procedure movement was more normally and performance restored. Follow the full link and sync procedure which advises this as step no. 1 (check the cluster seat.

Hope useful

F

 

[jbjennings]

Re: Timing 3-cylinder 65hp

WIll recheck! I may have to invest in a dial indicator....
Will check cluster pin (pin under carb that connects them??) as well.
Thanks for the responses.
JBJ

 

[jbjennings]

Re: Timing 3-cylinder 65hp

Found this method of taking a cheapo Harbor Freight dial indicator and using an old spark plug to adapt the cheapo indicator to the spark plug hole. Here's the link. Looks easy.
I appreciate you Alan and Chris....... sometimes it helps to have someone that knows how to do things right to motivate me to do mine right!
http://www.thumpertalk.com/topic/93...-15-dial-gauge-dial-indictor-ignition-timing/

Maybe someone else that works on outboards as a hobby can use this info as well.
LAter,
JBJ

 

[Fishcake42]

Re: Timing 3-cylinder 65hp

WIll recheck! I may have to invest in a dial indicator....
Will check cluster pin (pin under carb that connects them??) as well.
Thanks for the responses.
JBJ

Cluster pin is at the top of the carbs with a small roller that connects with the slider on the block. If I recall correctly, you are looking for it to sit really neatly with butterflies shut, you then bring throttle back and that would be true idle position for adjustment. Check/adjust this first and then check you idle timing making adjustment to 2-6atdc. Once set you max advance at cranking can be set more accurately. This is off top of head as I'm not near my manual at the moment.

Hope useful.

 

[Bob_VT]

Re: Timing 3-cylinder 65hp

Does the motor fall into this category??? Read this http://forums.iboats.com/engine-fre...q/timing-sync-merc-inlines-1988-a-168855.html

 

[Chris1956]

Re: Timing 3-cylinder 65hp

JBJ, I would think you want to synch the timing to the carb opening. That means that the timing spec for idle pickup, is set just when the carbs are ready to open. On my old 1500 distributor model that was 4-6* BTDC. Max advance was 21* BTDC.