TOPIC: Need Help - Merc 400 Points Gap

Guys(and Gals),

I finally took my magneto off to check / adjust the points. Problem is I don't have a manual for this motor (1960 Mercury 400).

Can someone recommend a points gap setting?

Thanks,
Gadabout

i'll take a picture of it.. but my book says .008 to .010 gap for points..for that motor just sounds a little low to me...

hope that helps you..

definitely is .008-.010, dwell 48 degrees. I do service on them if sent to me.

That does sound tight, but it is what it is.

Thanks guys. Appreciate the help. I'm hoping to be back out on the water this weekend.

Thanks again,
Gadabout

Dave,

Where are you located in case this does not fix my problem - engine stalls when shifting into gear. (I'm in Central Michigan.)

Gadabout

NYC Area. 1 914 310 7086

It sounds tight but being a old HD mechanic I tried .015 what you would set a HD mag at it made the dwell way off on my 650 the local Merc shop said the motor could not be fixed all I did was clean the mag new plugs and it has been running for 16 years now

I just posted the steps to polish points in this style magneto a day or so ago, so track that post down and things will work out just fine for you.
doc

I don't know how to include the link, but the post that Doc was referring to is titled:
"1956 Mercury Mark 55 E - how to "jump" start it."

Thanks guys for the additional info. The points looked pretty smooth. I just touched them up lightly with a points file (yes I am old enought to own one of those.)

They were set (or the rub block wore) to less than .005 thousandths. I can't believe it ran as good as it did. I was just having a problem of it dying when I shifted out of neutral into gear.

I'll put the timing light on it once I get it back together. Speaking of that - I'm assuming I should see to timing marks (magneto pulley and flywheel) line up at the first mark at idle and then advance to the second mark as I rev the engine?

By the way, my magneto cover was cracked / broken from someone overtightening the screws. Due to time and cost I ended up putting it back together with epoxy and fiberglass to reinforce it. Built like a tank now and should work great.

Thanks again for everyone's input!

Gadabout

Got the points adjusted and everything back together. Couldn't make it out to the lake but started it in a tub and it's running much better. Idle screw was turned way in before and had to keep the idle speed up to keep it running. Also, it didn't want to shift into gear without dying.

Now the idle screw is barely touching the magneto and it still idles at 1000 to 1100. Also shifts into gear with no problems. Probably still need to fine tune the carbs on the water, but way better than it was.

I think the tight points setting was causing my idle timing to be retarded (points opening late due to hitting the lobes on the magneto shaft later or further up the "ramp".

Thanks for all the good advice. Couldn't keep the old girl running without you guys!