merc 500 timing

I have a 1965 merc 500 (50hp) ,when I puchased the motor the distributer was taken off. I also have a 65hp that came with it for parts. I replaced the coil and points from the 50hp with the parts from the 65hp. I timed it per the instructions I aquired from the e-net, the flywheel mark lined up to the dis. pulley arrow. the engine fires strong or seems to but all I can get it to do is pop every once and awhile,it will not run at all. Am I timing it right or what might be my issue with this engine. I love working on old anything mecanical so I would really like to get it running. Anyone with any ideas as to what i'm doing wrong. THANKS!!

Re: merc 500 timing

Try this link out. it may steer you in the right direction.

http://www.maxrules.com/timingindex.html

Other things to check are wiring for cracks, coils for cracks. Distributor cap for cracks, hmmmmm yah just look for cracks and corrosion.
A carb rebuild and a link and sync might be in order as well.

Re: merc 500 timing

Just a thought...
My '73 Merc 500 has two identical marks on the flywheel. One points to #1 TDC on the timing decal/sticker the other aligns with the dist pulley. Make sure you're lining up to right marks.

Re: merc 500 timing

thanks for the info. I put a spark plug on al the wires and turned the motor over and they are all firing i probly dont have it timed right

Re: merc 500 timing

thanks for the info. I could only find one mark,very small line on the edge of the flywheel,lined eveything up still wont run.

Re: merc 500 timing

Heres an 'old school" trick for finding the TDC on any cylinder. You remove the number one plug and screw in a candle. Turn engine over slowly with coil disconnected untill you hear it "POP OUT". By doing this you can find or verify the correct timing order .This rules out any crossed wires on any engine new or old 2 stroke or 4, makes no differance.( note if any of the candle shavings fall into the cylinder it wont matter)

Re: merc 500 timing

The mark on the flywheel is used to line up the distributor, and the flywheel. It has little to do with actual timing. If you remove the top cover of where the timing belt is, you will find a line on that pully. For correct timing those line must meet up. If they don't the belt has to come off, and the then you match up the lines, and reinstall the belt. These motors are timed mechanically with a gauge or a dial indicator. Once timined, you can add marks, so in the future you can just use clam's timing procedure, with a timing gun.

Re: merc 500 timing

weldbilt17,
Does your motor still have a #1 TDC / timing advance decal/sticker on the top cowling mount around the flywheel? If it does, I think the single mark on your flywheel needs to point to the "#1 TDC" mark on the decal (when cyl. #1 actually is at TDC) then check the position of the distributor pulley arrow. It should point directly towards the center of the flywheel hub. That's the condition of my 500 when all lined up properly. My second flywheel mark then lines up with the distributor pulley arrow and an imaginary line between the center of the flywheel and the center of the distributor pulley. If you're sure its a timing problem it can't hurt to try. Also make sure your plug wires aren't crossed and are connected in the firing order stamped in the casting near the plugs.
The timing light is used to check the position of the flywheel mark against the timing advance decal with the engine cranking to check your max. advance setting.

Re: merc 500 timing

are you refering to the cover on the ditributer or the flywheel.thanks

Re: merc 500 timing

I can't seem to find a decal for tdc anywhere.I think my next steep is to use a screwdriver to locate the #1 to tdc then line the distributer to center off that.thanks for the info ,it is appriciated

Re: merc 500 timing

On those motors there was no timing decal. They are timed mechanically, using a jig, (.235 advanced & .015 advanced). To correctly install the distributor, you need to line up the line on the flywheel, with the line on the
distributor. (note this is not TDC of number one, but actually about 20 ATDC of # 1 cylinder) Mechanical timing is done on cylinder number 3, on most motors, of the inline 6's, number 4 on the others ( I might be wrong on the others I only have a 6). First thing is to get the disributor in correctly, with the tang facing away and the lines, lining up. Once that is done, you can do the mechanical timing using a dial gauge. That way you can correctly set up throttle stop, and timing advance stop. Keep in mind, you may have to set up the point gap, and dwell on top, if someone has messed with the distributor.

Re: merc 500 timing

Thanks fuzzytbay, I was starting to think that mabe I had forgotten how to read. Thats what the literature said from that (max something web site) that I have. So I have the dist. and flywheel correct but I'm not sure about the mechanical timming on cylinder number three. I've been messing with motors since I was old enough to turn a wrench, but the last year or so is when I started messing with boat motors,there a different animal altogether,but I'm learning and I appreciate the help from anyone willing to help. I'll do the same if knowledge permits.

Re: merc 500 timing

The setup procedure is pretty simple, all you need is a dial gauge, and an old spark plug. Remove the ceramic portion of the plug, by cutting the ring, where the bottom of the plug (metal) part meets the ceramic part. Then remove the anode, and the ground portion, (the part you move to gap a plug).
Depending upon the type of dial gauge, you can tap a thread on the inside of the plug, or just insert the dial gauge, and glue it in place with hot glue.
Then follow the procedure in the link. Just use the dial indicator to make the advance measurments. Ie find TDC, set dial indicator to zero, move the flywheel (clockwise I think) untill the gauge reads .235. thats where you set your max advance stop at. Follow the procedure for the idle advance (.015) advanced i think, and the rest of the link and sync, and your ready to hit the water, (you hope).
Once you have done this, mark out the proper timing marks on the flywheel, and set up a timing pointer. Then you can just do it using Clam's method, should the need arise again.
Those motors are pretty easy to trouble shoot. if you have good compression, and spark, its normally not much to figure out the rest, of "why it won't run".
One note, I'd give some lee way on the max advance, the book say's 34 degrees, I'd be more inclinded to be closer to 32 than 34.

Re: merc 500 timing

Thanks for the info,I'll put it to use

Re: merc 500 timing

I had the same problem with my 64 merc 500, I cleaned the points etc , Aligned the timing marks(small arrow on mag pulley) still not running, then moved timing belt 1 tooth and motor purred like a kitten.

Re: merc 500 timing

I'll try that. thanks