Just got my OMC manual, now a question about sync...UPDATE

[mamm7215]

So I'm all ready to tear into a proper link 'n sync but I have a question about the cam alignment. I've read here and in my Clymer and Seloc manuals to adjust the cam follower to the upper cam mark but my OMC manual for my '81 J90tlcim says "Manually advance cam against cam follower roller. Lower mark on throttle cam should align with the center of the cam follower roller as the carburetor throttle shaft levers begin to rotate." LOWER mark? There's the one thick top mark, one just under it and another near the bottom of the cam. I assume the lower mark is the one just under the top mark. It also says Start next to it in the middle of the cam. I'm also assuming I do this with the cable disconnected, and re-adjust the cable to the linkage once done...
Just curious to see the manual says to adjust to the lower mark...anyone find this for their motor as well?

 

[mamm7215]

Re: Just got my OMC manual, now a question about sync...UPDATE

So going step by step through the factory manual was a great help, a lot more straightforward on the link 'n sync and less to do I found. Got the timing pointer set properly. Got the butterflies sync'd up properly. My cam roller is worn flat in a couple of places so I'm going to get another one but I got the LOWER mark centered to the roller just when the butterflies start to open as per the manual. Put my new power packs on, did the idle timing, set the TOP mark to the center of the roller at 4degrees holding the warm up lever in position. All good so far. It's idling better but I'm still getting a good miss every so often at idle. Spark on the tester seems good at 7/16. Compression is 120 all four. Fuel is there, pump is good. I redid plug wire #4, I pulled the wire off #2 at idle and it died, pulled wire off #4 and it evened right out. Move wires, followed to #2 so I redid the wire. Thought I had it. Still a slight miss. Tested starboard bank. Pulled wire #3, killed engine. Pulled #1, again idle evened right out. Redid that wire. Still slight miss now though the motor is running with a lot less smoke than before. I guess I'll test the coil next but they're all new, few months old. This motor's been overheated pretty bad in a previous life. I've got new heads and gaskets on it, new water deflectors, stats, etc. Been reading like a banshee on these boards and very gratefull for the help. I'll read through the manual more tonight, too late to work on it more. What does it typically mean when you pull a plug wire and the idle evens out? Plugs are fairly new as well, but did get oily so I cleaned them off. Is that enough? I can just get new ones tomorrow.
Thanks.

 

[jimdd810]

Re: Just got my OMC manual, now a question about sync...UPDATE

might be time to do a carb clean and overhaul. sounds as if your dropping a cylinder or 2 and when you talk about oily plugs sounds as if your running to rich. You dont want to run a motor for long when its dropping a cylinder could have a catastrophic failure. You did the right thing by getting a factory manual.

 

[mamm7215]

Re: Just got my OMC manual, now a question about sync...UPDATE

Sorry I should have mentioned I just rebuilt the carbs as well. Put a wire through all the orifices (but didn't remove any, don't have the tool), sprayed with carb cleaner and blew them all out. Set the floats, had them on and off twice double checking for cleanliness. One thing I noticed tonight was as I was watching the carbs while the motor was idling, there appeared to be fuel in one of the small brass "ports" at the front of the top carb, between the two butterfly throats:

I'm not sure what this would mean. One thing I also haven't done is inspect the recirc hoses for flow to the cylinders. It's possible they have some blockage but would that cause a miss or idle issue?

 

[mamm7215]

Re: Just got my OMC manual, now a question about sync...UPDATE

bump

 

[hayuuga]

Re: Just got my OMC manual, now a question about sync...UPDATE

Hi
What size is your carbs?
Is it 1 3/16"



best regards

David

 

[mamm7215]

Re: Just got my OMC manual, now a question about sync...UPDATE

1 3/16 or 1 5/16. I think 1 5/16, i'll look tomorrow