Throttle cable question

[tlewick1]

Mercury 1150 (1978); I'm trying to set up the throttle and distributor. It doesn't seem like the throttle will revolve the distributor fully. Either, I can set up the throttle cable to open the carb valves, but it won't pull the distributor back to where the spring (on the distributor) takes action. Do I need a new throttle?

 

[Chris1956]

If it is a MerControl, it should work. Those motors need the idle pickup timing set, the max spark advance set and the throttle stop set. One of your settings could be off.

Look at the plate on top of the distributor. You will see idle stop, throttle stop and max spark advance set screws. You should get a service manual and check the motor to assure she is timed correctly and those screws and the throttle cable is adjusted correctly.

 

[Chris1956]

Just so you know, the distributor will stop rotating at 21* BTDC spark advance, and you should be able to push the throttle open more to full open the carb throttle plates.

 

[GA_Boater]

If what Chris said doesn't work and the carbs don't open fully, try greasing the Zerks on the distributor. Sometimes the grease hardens when it ages. I had to tear mine apart to clean out the old, hard grease and after re-greasing, it works like a champ. Our motors have a similar setup.


Items 8 and 36 in the diagram for your 1150;

 

[tlewick1]

Thanks for your responses. The distributor can rotate by hand, but I've had to advance the throttle stop completely forward (screw it in all the way) in order for the carbs to become wide open after pulling the throttle. Is my understanding of this right: the rotor and cap are able to rotate, so that depending on the positioning, the spark can fire btdc when the engine is running at higher rpm. And I need to adjust the stops so that it doesn't fall past that? The manual says I'm shooting for 4-6 degrees btdc for idle (?) and 21 degrees at max spark?? If I take the cap off and mark where the rotor aligns with the contact at tdc, and then measure 6 degrees and 21 degrees from that point, theoretically the idle stop and max spark should stop the distributor from rotating after those points?

 

[Chris1956]

Your motor should have a timing decal and a timing pointer. Those are what is used to set idle pickup timing and max spark advance. Do you have those parts?

 

[tlewick1]

Yes but how can I run a timing light if the engine keeps stalling during idle? (The powerhead was off so I've needed to redo everything.) I need to atleast get it close, and then do the fine tuning later

 

[Chris1956]

Actually, you can set idle timing and max timing with the engine just cranking and not starting. Remove spark plugs 2-6, install them into their wires and ground their bases. Remove prop. Advance throttle until carbs are just about to open. Install timing light on cylinder #1 and jumper solenoid to crank motor. Adjust brass collar on midsection of distributor to set spark advance to 4-6* BTDC. Set throttle full. See carbs are fully open. If not adjust throttle stop until they are fully open. Crank motor and observe spark advance. Use max spark advance screw to set it to 21* BTDC,

When you are running the motor and setting the carbs, set idle stop screw to the desired idle speed, and adjust throttle cable to push throttle closed.

 

[tlewick1]

Why do I have to remove spark plugs 2-6 and the propeller?

 

[Chris1956]

Your remove spark plugs 2-6 because you do not want the motor to start up, and run at full throttle in your driveway, with no load or water. You remove prop, to protect your legs and bystanders, while you are cranking the motor in gear.

 

[tlewick1]

I see. Thanks for all your help, Chris. Actually, I have had the engine run away on me-- hehe. The bearings didn't seize or anything, but I hope I didn't cause any damage that I'm not seeing.