Need some Sync and Lync Handholding for an '89 70HP

[sumocomputers]

Need some Sync and Lync Handholding for an '89 70HP

I have been avoiding this procedure, mainly because it calls for some things that I don't have or are hard to get, and looked pretty complicated.

Reason is that I am having some rough idle/starting issues, and figured since I don't know how well it was previously maintained, figured it should be done as a matter of course.

Now that I have decided to dive in, I had a few questions below. Hoping someone else can help me get the confidence to do this properly.

Thanks,

Chris


1. Set Timing Pointer
Calls for OMC Piston Stop (384887). Can I use something else for this?

2. Throttle Plate Sync
Understood.

3. Idle Speed
Understood.

4. Cam Follower Pickup
-Calls for a Throttle Shaft Amplifier. Can I use something else for this?
-Also, I really don't understand this step at all, nor understand the goal of the adjustment.
*See Photo from Service Manual Here: https://www.dropbox.com/s/sa1mfh0b9jfi1c7/2015-04-19 15.34.51.jpg

5. Throttle Cam
Understood.

6. Wide Open Throttle Stop
-Calls for advancing the throttle to wide open with engine off. I recall reading that it is not good to put your motor in gear without it running.
-Do I need to have someone turn the prop while doing this (not running of course)?

7. Max Spark Advance
NOTE: I have read the Top Secret Post from Joe Reeves on WOT Timing Procedure.

-Calls for a Test Wheel in a Tank at 5000 RPM, neither of which I have. Looks like I might be able to follow the Joe Reeves method, but sure looks scary, and last thing I need to do is damage a piston or three.
-Can I use a regular old automotive Timing Light from Harbor Freight?
-Any other tips to do this safely? Or maybe a dumb question, what happens if I skip this step?

 

[WernerF]

1. Set Timing Pointer
If you assume that the timing pointer is disturbed, you can remove the #1 cyl. spark plug and check that the piston's TDC position corresponds to the 0? marking on the flywheel. The service manual shows a more accurate method using the piston stop. The piston stop itself has no measuring function, it just makes sure that the piston is at the same position before and after TDC. Halfway between those positions is TDC. So if you want to adjust the timing pointer that way, you may take an old spark plug and weld a 1" piece of metal on it (solid enough so it does not break off and fall into the cylinder). Sand it round a little in order not to scratch the piston gound.

4. Cam Follower Pickup
The throttle shaft amplifier is simply an alligator clip with a piece of solid wire. It helps you see the first movement of the throtte shaft. When the throttle shafts begin to move, the roller must touch the cam right at the mark. Note that the roller has a sleeve on it which is missing quite often.
BTW the Solec manual shows an easier way and it works too. It simply says: Adjust idle rpm (throttle butterflies closed), then adjust the gap between cam and roller to 0.010" (feeler gauge) and cam marking to roller.

6. Wide Open Throttle Stop
Turnig the prop will work. If you are alone and the remote control is close enough to the motor, turn the flywheel clockwise while shifting. (CCW might hurt the water pump impeller).

7. Max Spark Advance
None of us ordinary mortals have a test wheel and a test tank. Yes, you can use an automotive timing light. Best if is has an inductive spark plug clip. I suggest, you make the adjustment using Joe Reeves method and verify your adjustment at WOT on the water with a second person on board. Paint the 16? through 20? markings on the flywheel in white or silver color as it is hard to see them in daylight.
BTW there has been a service bulletin calling for reducing the max. spark advance to 17?BTDC.

 

[sumocomputers]

WernerF
Thanks for all the great info. I think I am ready to dive in.

What are the implications if I do all the other tests and simply don't perform the Max Spark Advance?

I will see if I can find the service bulletin on the 17?BTDC thing (I think mine has 19?BTDC on the sticker and service manual).

 

[Fed]

Just a point of interest Sumo although the manual doesn't specifically say not to turn the motor CCW it does go through a slightly convoluted way of using a proper adjustable piston stop tool to avoid CCW rotation.

Often it's not what the manual says rather it's what it doesn't say.

IE: Position the piston in approx the right place then wind the stop tool down until it touches, then lock off the tool while holding the piston firmly against the tool. Then rotate CW until it comes back up & touches the piston again.

It seems to me they have gone to great lengths to avoid CCW rotation so they must have their reasons, guessing W/Pump.

Adjustable piston stop tools are cheap enough.

 

[sumocomputers]

Fed
You saying I can get a cheapie piston stop tool, no need for the OMC original? Never even thought about that!

I am looking at something like this:

http://www.amazon.com/MaxPower-12614-Steel-Piston-Stop/dp/B00570BWUU

 

[Fed]

I'd get an adjustable one, put adjustable piston stop tool into google images and you will see the difference.
Being adjustable you can firmly seat the tool in the sparkplug thread the slowly screw down the adjustment to meet the piston top.
http://www.amazon.com/Competition-C..._sim_lg_5?ie=UTF8&refRID=1SDE5D1CNME3SD6PBNDC
Needless to say it has to fit your plug thread.

 

[WernerF]

The max spark advance is generally a stable adjustment. It is affected when
- someone has disturbed the adjustment
- the plastic bumper on the adjustment screw is deformed or missing
- the flywheel is removed (can affect timing pointer)
- the timer base coil is removed
- the powerpack is replaced

BUT for the thermal health of your motor this adjustment is the most important one.

 

[sumocomputers]

No Title

The service manual says you must remove the throttle cable before doing anything (funny enough, it doesn't tell you to reattach it for the initial idle speed setting).
Can I just remove the nut (A in the attached photo)? I just hoping I don't need to do a bunch of readjustment if I need to unthread it.

I ordered the adjustable piston stop tool, and looking at getting a self powered timing light like this one (hope it's bright enough or may have to get on the water really early):
http://www.amazon.com/ESI-130-Self-Powered-Timing/dp/B00063WM1Q

WernerF
You mentioned there was a Service Bulletin recommending going from 19?BTDC to 17?BTDC. I think I found the SB # which is SB2271, but for the life of me cannot find the actual document. I want to make sure it applies to my motor (most references seem to be for '91 and later). I am thinking that I could just go for 18?BTDC (14 with Reeves method), since that would be in acceptable range of both 19 and 17. My model is an '89 J70ELCEM.

Last question, I am thinking if I do all the tests except the Max Spark advance, and then just take it out in the water at 5000RPM and check with my light, it might already be in spec, then I don't have to do anything, right? Or is this wishful thinking? I don't think any of the items WernerF mentioned apply (I still need to inspect the plastic bumper on adjustment screw).

 

[Fed]

Do you have a genuine OMC manual for that motor?

The cable is adjusted last so even if you undo nut A you will still have to adjust at B & C when you're going to reconnect.

From my '88 90hp but I'd say typical across the OMC range of that era.

 

[sumocomputers]

Yeah, I have the genuine manual, and I see what is involved now for the throttle cable adjustment. It doesn't seem too hard now that I really read it.

The thing that is weird is that step 3 (Idle Speed) requires you to be in the water in gear (not on trailer or tied to dock), and although it doesn't mention it, you will have to reattach the throttle cable, and the detach it again for steps 4-6, then reattach and adjust before step 7 (Max Spark Advance).

I was hoping to do steps 1-6 all on the trailer, but it doesn't look like there is a way around it. It is just really awkward to make the adjustments for steps 4-6 while inside the boat, so I will probably just have to retrailer it.

 

[Fed]

Your idle speed adjustment only alters the timing and at idle the carb butterflys stay completely shut so you don't have to disconnect any cables to adjust the idle speed.

 

[sumocomputers]

Your idle speed adjustment only alters the timing and at idle the carb butterflys stay completely shut so you don't have to disconnect any cables to adjust the idle speed.

I understand what you are saying, and sorry to be a pain.

But according to the instructions, before starting step 1 you remove the throttle cable, and reattach just before step 7, with no re-attachment in-between.

Problem is, Idle Speed adjustment is in step 3 and requires the cable to be attached and in the water, or so I am assuming.

How do I reconcile that?

Maybe I misunderstand, but thought all the steps had to be performed in order.

 

[Fed]

You're doing better than me my manual (different motor) doesn't even mention reconnecting the cables, all it says is to perform the adjustments with the cables removed.
I'd get it idling warmed up on the muffs in neutral at about 1000-1200 rpm then reconnect cables and adjust idle speed on the water.

 

[sumocomputers]

You're doing better than me my manual (different motor) doesn't even mention reconnecting the cables, all it says is to perform the adjustments with the cables removed.
I'd get it idling warmed up on the muffs in neutral at about 1000-1200 rpm then reconnect cables and adjust idle speed on the water.

Sweet, I was leaning towards that for practical reasons.

My manual doesn't mention reconnecting the cables for idle speed adjustment either, but it does mention to put it in water in forward gear unrestrained, so kinda assumed you would need the cable reattached to do that... Still sort of impractical

 

[WernerF]

No Title

Actually you're right, you can't float on the water adjusting idle rpm with the cable disconnected. But if you make sure that the trottle lever is always pressed against the idle adjustment screw, you can leave the cable connected. If you have to turn the idle adjustment screw more than say half a turn, you need to readjust the cable so the throttle lever is pressed against the idle adjustment screw again. Or, in the other direction, the force against the idle screw doesn't become excessive.

I think 18? BTDC will work. This is the bumper of the max spark advance screw that I mentioned above. Foto is made from starboard side. Adjustment is made from port, you need a tube wrench to get deep enough, if I remember correctly 7/16" or 11mm.