1970 Merc 1100ss

[RubTJicon]

As I stated in another post, my brother and I have started working on restoring a boat that was given to him. The motor seems to start and run great until we put it on the lake. Then starting become a real pain, and it does not like to idle, you have to manipulate the timing lever to keep it idled up.

I'm looking for tune up advice. Is the Champion L78V the proper plug for this motor ? Can you still buy carb rebuild kits ? Just give me some pointers on getting it running like it should.

I'm an off roader normally, so this is very far from anything Im familar with.

Thanks in advance.

 

[emckelvy]

Re: 1970 Merc 1100ss

Hi, if it's truly an 1100, that motor was only made from '66-'67.

An L78V plug is too hot for that motor. The original mfr's specifications for the 1100 equipped with electronic ign were a Champion L-19V surface-gap (Permagap) plug.

The current equivalent of the L19V would be an L76V.

The L78V is one heat range hotter so wouldn't be a good choice unless you were idling all the time.

Note that the early, non-cdi versions of the 1100 used an L4J plug which was superseded to an L82C.

Here's some links to model/year info for all the versions of the 1100, so you can positively identify yours:

http://store.eastcoastmarineservice.com/category_s/843.htm

http://store.eastcoastmarineservice.com/category_s/830.htm Note that the pic for the L76V spark plug is incorrect, doesn't show a surface-gap plug.

http://store.eastcoastmarineservice.com/category_s/847.htm Same comment on the spark plug pic.

Check out all the stuff there, they have a lot of parts for the ol' Mercs.

The Mastertech Marine site has plenty info for the older motors, another great resource:

http://www.maxrules.com/#

HTH & have fun!...........ed

p.s. check sites like www.boats.net or www.crowleymarine.com for parts diagrams for your motor. You can still get most 'soft goods' type of parts, carb 'packing kits' (gaskets for rebuilding), floats, needles, seals, etc. A lot of these parts were commonly used for many years so the aftermarket picked up on them as well as Merc still providing. Check the repair FAQ for tons of hints on awakening a 'sleeping' motor, rebuilding carbs, etc etc etc.

 

[RubTJicon]

Re: 1970 Merc 1100ss

Thank you so much ! I guess it is a 1967 model, it looks identicle to the one in the pic here http://store.eastcoastmarineservice.com/category_s/847.htm .

It seems to be a tight old motor. It dies instantly as soon as you cut the ignition, no loose turning afterwards. My brother is working on a new paint scheme to get rid of the ugly brown and gold, and Im working on the motor. Im going to rebuild the carbs, change the plugs, and get the prop repaired or replace it with a composite prop. But if a new prop is in order, it will come after we test it with a tach.

Also, can you rpm test with the motor in a barrel of water, or does it have to be pushing the boats weight ?

 

[usskydvr]

Re: 1970 Merc 1100ss

You need to test with the boat pushing. Look for a link-and-sync procedure on forums or the web. This sets the carb butterfly opening and distributor timing advance and is critical on these old Merc motors. Why are you planning on putting a composite prop on? Also, there is no run after on these motors. One last point, DO NOT set the ful advance timing to the original
36 1/2 degrees, Set it to 34 degrees. This is due to the lower octane of current gasoline.

 

[RubTJicon]

Re: 1970 Merc 1100ss

Thanks for all the help guys. This place is great.