Can Someone Clarify Link & Sync 1991 9.9hp

[smeltjr]

This is my dad & uncle's and I advised that I would look at it. Pull start and hard starting on the first time in the day. He says it runs well but may take 20 pulls the first time and replicate itself if it gets tilted for awhile. Otherwise starts easy the rest of the day. Too cold to fill up my barrel so I hav looked at the following scant things so far.
1. Spark is strong, blue and jumps a good 1/2"
2. It has thumb compression and I have not hooked up the China Freight tester yet.
3. It has updated carb top cover 337833 - it has been looked at twice for this and I am not sure by whom but the 1st guy allegedly had the choke upside down.
4. The roller does not have any gouging on it but it is touching the cam plate all the way throttled down and the the throttle butterfly shaft is turning BEFORE the roller meets the cam line. That is the question.................

I have read the ramblings and searched here and it appears that this roller should NOT even be touching the cam plate until just the moment that it gets to the line at which time it should also just be opening the butterfly and shaft? I will adjust if needed but can someone clarify and if this adjustment could possible be affecting the starting condition?

They bought the motor new and it only gets used a few hours per year and otherwise looks in really good condition. The old guts are in their 70s and don't need to pull any more than a couple times. Maybe elec start if I could find a cheap flywheel...............................
Thanks

 

[Bob_VT]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

best 9.9 resource available here http://forums.iboats.com/engine-fre...aq/9-9-15hp-omc-engines-machinist-158087.html

 

[smeltjr]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

Yup - thanks Bob and I have indeed been through all of them. Again, too cold to get it in the barrel so just making some observations here first. Simply should that roller even touch the cam plate until it gets at the mark? I am aware that if its like my 3 QD's and JW that the throttle plate should just start opening when the roller gets at the line on the plate. I don't know how this affects starting. Didn't see thes in the ramblings. Thnx for response.

 

[poida]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

I'd put a carby kit through it.
Yeah the roller will touch the cam plate, it should start to open the butterfly at the mark or a little before it.

 

[OptsyEagle]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

I am not personally familiar with the 1991 model but for link and sync with the carb on the motors I am familiar with, the motor's throttle cam will have a mark. The carb roller should just touch this cam at the exact point of that mark. If it doesn't, hard starting will be your biggest problem and reduced performance from improperly set spark advance timing, will be the next.

On my motors there are two 5/16" hex nuts on the starboard side of that cam. If you loosen those nuts the cam can be adjusted back and forth to set this properly.

The other hard starter issue is the choke. You will want to determine that it did get fixed properly. The first and easier check is to look at it. When you pull the choke lever does it look like the butterfly closes. It should.

 

[Silvertip]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

Hard cold starts (first of the day) is almost always lack of fuel (choke/primer inoperative) or improper starting procedure.

 

[the machinist]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

Yes, cold starts are usually fuel related, this can also be slightly altered by turning the idle knob to as far rich as you can (just for starting) then back to your preset idle position after it warms up.

I thought I covered that in my "Ramblings", but will check & reword it if not covered. Maybe it is on only one article & not on others.

 

[smeltjr]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

Leroy - I do remember on the knob to richen at start. It is th timing I am seeing and if that will affect anything. I will re-read as well. Appreciate your response and your articles are GREAT. Thanks for the value you have added to others.

 

[AlTn]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

try adjusting your linkage to reverse what you have in #4 of your initial post;i.e. the ignition timing is slightly retarded and the throttle actuation is advanced when set for initial start.
slightly advanced ignition timing on cold start is what you want to achieve. I fooled with a '90 model 9.9 and found that along with the mixture screw on the carb it was necessary to adjust the idle knob on the end of the throttle handle. If you go into the carb, the orfice plug <main jet> screws into the side of a plastic "well" and a small plastic tube runs from this well up to the idle circuits in the plastic top. Try not to damage that well as it is "pricey". Note that each screw on the plastic top is numbered in the order that is to be tightened for the final time. Any warping of that top can lead to a lean condition which makes starting more difficult. Good luck...you might try ebay for a factory workshop manual for that motor if you are now the head mechanic for Dad and your Uncle.

 

[kbait]

Re: Can Someone Clarify Link & Sync 1991 9.9hp

Check the new plastic carb cover for any hairline cracks.. especially near the needle location. If air passes through to the needle valve, it won't start worth a damn, and likely not idle well. I have successfully sealed said crack w/jb weld.. plastic carb covers are expensive.