7.5 comet lightning

tnuck

Cadet
Joined
Sep 17, 2009
Messages
6
Hello everyone---new here. Just purchased a 7.5 comet lightning and it ran in all gears in a barrel at the sellers house. On the water it ran ok in reverse and neutral, but bogged in forward. Any ideas. It sat for two years. I'm expecting impeller and carb, but any other things to look for before taking it to the doctor? I'm not an expert or mechanic. Any help would be appreciated.

Thanks in advance,
Thomas
 

7920hpMercury

Petty Officer 2nd Class
Joined
Mar 13, 2009
Messages
111
Re: 7.5 comet lightning

Could be a lot of things.

I would get the serial number and check 1st post here for year.

Get a service manual.

You are on the right track cleaning carb, change impeller, and check all wires & grounds as it sat for 2 years.

Good luck and great motors.
 

tnuck

Cadet
Joined
Sep 17, 2009
Messages
6
Re: 7.5 comet lightning

Thanks for the help. Where can I get a manual and I'm having trouble finding the post you described. Any chance you could send me a link.
Thanks,
Thomas
 

7920hpMercury

Petty Officer 2nd Class
Joined
Mar 13, 2009
Messages
111
Re: 7.5 comet lightning

Here you go, it is the first post in this section:

http://forums.iboats.com/showthread.php?t=264123

For manuals, once you know the year (or it is very helpful to know the year), check ebay for a Mercury factory manual or a Seloc manual. You can also order a Mercury factory manual direct from Mercury, but they seem to be getting more expensive. You can find one on ebay if you are patient and have the time.

Good luck.
 

MSZ

Seaman Apprentice
Joined
Jul 18, 2009
Messages
34
Re: 7.5 comet lightning

Look up your motor here:

www.oldmercs.com

Never heard of a comet lightning. Look up the motor you have and report back.
 

tnuck

Cadet
Joined
Sep 17, 2009
Messages
6
Re: 7.5 comet lightning

Thanks to all. As for comet lightning, it is a sticker on the inside on the engine. Figured it was its name, may still be. Must be a rare find worth a gazzillion million dollars!!!!!!! Know nothing about it though. Will let you know what I find.
Thomas
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: 7.5 comet lightning

The lighting is cast in the block denoting the block was a 9.8 casting and the comet sticker tells you that it was machined to 7.5 specification's, so what you have is a 7.5 HP and if you look in the area underneath of the nanes there should be a serial number stamped in the block, that will tell you the year.
 

MadtownWI

Cadet
Joined
Sep 3, 2009
Messages
13
Re: 7.5 comet lightning

Still haven't found the year for my Comet Lightning. I've read every sight I could find on serial numbers matching the year manufactured but nothing gives the year of mine. Serial number A171960, plain as day on the ID tag on transom mount. Unmistakable A171960. Anyone have a clue?? :confused:
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: 7.5 comet lightning

Since the A did not appear before 1986 and the starting serial number for the 8HP in 1986 was A197112 and 1985 was the last year of production for the 7.5 that would make the engine with a build date of 1985 and a 1986 selling year, to the best of my knowlege.
 
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