Need help to set timing

[Zraden]

Hello.
So... I've never worked on a carb and dist engine in my life. I'm learning though. I have a 1990 merc 4.3 that we want to hook the timing light to and make sure the timing is ok. Question is, lol ... how do you do it? The engine number is 0C873497. How many degrees should be set and how do you fix it if its out a few?

 

[achris]

Re: Need help to set timming

Re: Need help to set timming

... I've never worked on a carb and dist engine in my life.

You must be a youngen'....

Checking the timing is quite simple on your engine. It's a Thunderbolt IV system, so no 'base mode' to set up...

I assume you have the following tools (and know basically how to use them). Timing light (best to have one with a tacho built in), a hand-full of AF spanners, assorted screwdrivers...

Connect the timing light to the battery (assuming it's a 'powered' timing light) and the pick-up to the spark plug lead of #1 spark plug. There may be an arrow on the pick-up, that should point towards the spark plug. Start the engine and let it warm up. Make sure the idle speed is down around 650-700rpm. Now point the flashing end of the timing light at the timing marks on the engine front cover. You see a line on the crankshaft pulley that appears to freeze with the flashing of the timing light. That line needs to line up with the indicator tab at the 8 degrees BTDC (before top dead centre) mark. If it doesn't, you need to loosen the clamp plate holding the distributor down and carefully turn the distributor until the line on the crankshaft pulley is in line with the 8 degrees BTDC mark, then tighten the clamp plate bolt and recheck the timing.

The service manual you need is THIS one... Have a look at section 4B, page 17....

Chris....
BTW, your engine serial number is missing a digit....

 

[Silvertip]

Re: Need help to set timming

Re: Need help to set timming

#1 cylinder is the front one on the port side of the engine.

 

[Zraden]

Re: Need help to set timming

Re: Need help to set timming

Does that clamp your talking about hold down the rotor as well? I tried to change it out last night but couldn't get it off. I didn't see any screws holding it down either. The only instructions I could find were to just pull it off but I'm not sure that's right.

 

[Bondo]

Re: Need help to set timming

Re: Need help to set timming

Does that clamp your talking about hold down the rotor as well? I tried to change it out last night but couldn't get it off. I didn't see any screws holding it down either. The only instructions I could find were to just pull it off but I'm not sure that's right.

Ayuh,... The clamp holds the distributor housing,...

The rotors are glued on, Bust it off with pliers, just be careful of the shaft...

 

[Zraden]

Re: Need help to set timming

Re: Need help to set timming

Awesome! Ty for the info