Anyone ever time a 1988 merc 115 6 cylinder? Need cranking timing BTDC or ATDC

[Buck Horn Deer Farm]

I have the Seloc 1965-89 repair manual and on page 6-23 paragraph 5, 6, It says crank and adjust primary pic-up...until "timing mark" on fly aligns with pointer (already adjusted to .464 with dial ind. and plugs are out and no idle stabilizer). The appendix says 5* BEFORE TDC. Not sure of that. When I crank and use timing light on #1, what should it be set at?
In a nut shell, timing light on #1 and cranking what should I see?

 

[Buck Horn Deer Farm]

ALSO.
If anyone has a different manual on this motor, would you tell me what it says for procedure on timing and what to set it at?
I have read Clam's post on procedure but not sure I understand timing event one.

 

[444]

Are you sure part of that process you are reading doesn't apply only to the older ones with a distributor?

 

[Chris1956]

ADI ignitions like you should have, have primary pickup timing set at 0-9* ATDC.

The .464" timing mark is to adjust timing pointer accurately. Set #1 piston to TDC, with a ruler/micrometer/screwdriver. Measure from piston top to ende of spark plug hole. Add '464 inches to that measurement. Adjust #1 piston to that measurement. Timing pointer should point to the .464" mark. If not, adjust it.

Remove spark plugs 2-6 and install them into their wires and ground their bases. Put timing light on #1 spark plug wire. Remove prop and set throttle to the spot when the carbs are just ready to open. Jumper starter solenoid (ign on), and read timing. Adjust primary pickup set screw to 0-9*ATDC. Adjust throttle to full. Crank motor and set max spark advance to 21* BTDC.

Install spark plugs, install flusher and run motor. Set idle speed to 900, or as close as you can get. Final idle speed will be set on the water, in gear, motor warm.

 

[jimmbo]

Chris1956, that was one of the clearest descriptions of how to do the sync and timing I have read.

 

[Buck Horn Deer Farm]

Thanks Chris 1956, Did all that and started it up. Runs rough and won't idle down less than 900 rpm. The carbs are fully closed and the only way to get the rpm down is to turn the primary screw in all the way until it wont move any more. I wish it would go more. It gets down to 700 rpm and It runs smoother there and the timing light mark is 12* ATDC when running at that speed. Could there be something not reinstalled properly?
This motor is new to me and was at a repair shop before I got it.

 

[jimmbo]

The idle speed adjustment is located throttle linkage arm on the port side on the engine(circled area)

 

[Buck Horn Deer Farm]

Jimmbo, I have the idle screw backed off so far it won't even touch the stop. What is stopping it from moving any closer to the stop is the arm from under the flywheel that moves the trigger won't travel any further to ATDC.

 

[jimmbo]

Have you disconnected the control cable, or removed the barrel trunion from its retainer?

 

[Buck Horn Deer Farm]

Jimmbo, Yes, the throttle cable is off, carb lever out of the way so carbs are closed, carb idle screws are out 1-1/2 turns, Idle speed adjustment screw is backed way off, it has no idle stabilizer box, timing pointer is set at .464 BTDC (#1 cyl with dial indicator),

With primary pick-up screw adjusted to 6* ATDC at cranking speed (2-6 plugs out and grounded) with timing light on #1, Reinstall plugs, it starts but very rough idle at 900-1000 rpm. With the the carbs closed and idle screw backed off as stated above, the only way to lower rpm is to screw the primary pick-up screw in. The further in it goes the smoother it runs, when it is almost all the way in the rpm will start to drop. When it won't screw in any more the rpm is down to 700 and runs smoother but not great.

 

[jimmbo]

When you say won't go below 900 rpm, is that in the water, in gear, with prop? Or on the hose with muffs?

 

[Buck Horn Deer Farm]

It is on muffs, and to get that 900 rpm it is at 12* ATDC.
I will put it in the pond tomorrow to set the idle.
1) What should I shoot for in forward gear for rpm?
2) Where should the timing be at that time?
3) And where should the timing be when the carb lever roller contacts the cam?

 

[jimmbo]

1) 600 -650 rpm in gear and warm
2) Timing at idle speed does not matter, it is what determines the idle speed and will vary with different props as the load on the engine will be different.
3) that is your primary pickup point so what ever the spec for your engine is. Not all ADI engines have the same spec. I know Chris 1956, said 0-9* ATDC. You said your service book said 5 BTDC. That setting is important as it will affect how the engine responds to the throttle control, so you really need to get it correct. I can't look it up as I gave my late model inline mercury service manual away about 8 yrs ago
The spec might be on a white label on the front cowl support.

 

[Buck Horn Deer Farm]

Well, I found a problem with the bottom carb while running it in the pond. The carbs were rebuilt just before I got this motor and the butterfly on the bottom carb is NOT closing all the way. It feels like it is because the butterfly is screwed to the shaft off center making contact on one side but not the other allowing air through. I will pull it and fix it and try again tomorrow. Hope that will help get the rpms down.

 

[Chris1956]

The adjustment is to loosen the top screw where the plastic throttle rod attaches to the carb throttle rod. The carb shutter can be adjusted to close fully.

 

[Buck Horn Deer Farm]

OK, got the butterfly to close all the way. Before I go back to the pond to test it I would like to know for sure where my primary timing should be set at.
The serial # on the mount and block stamp is A180434. Based on that and because it has no distributor I assume it is a 1988. Can anyone verify that?

 

[jimmbo]

The only place where that serial shows up that I can find is as a 1985. What colour are the stripes on the cowl
As for the pickup timing... Is there not a white sticker/decal on the front cowl support/frame with that info?

 

[Buck Horn Deer Farm]

OMG are you kidding me. that sticker has been there all this time and I never saw it. It is only about an inch tall and black with white letters. It says 6* ATDC.
I will set that and head back out to test.
The colors are all brown, dark on top .... tan on bottom. Serial # A180434. What year is it?

 

[jimmbo]

Brown stripe cowls were 1984 and 1985. I would say you have a 1985 engine, cowl and serial #

1984 115


1984 115 with 1971 cowl

 

[Buck Horn Deer Farm]

Yea it looks like the brown one in the pic. Do the 84's have two switch boxes and six coils?