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120 hp 4L mercruiser 4cyl engine tune up specs

snuffy01

New member
"I have a 120 hp 4L mercruiser

"I have a 120 hp 4L mercruiser 4cyl engine (1968?). I need tune up specs, ie; plugs, points, timing and carb idle settings, (rochester 2bbl). Anyone?"
 
"SN: 3825578 and below uses A

"SN: 3825578 and below uses AC CR44N, gapped at 0.035", point gap is 0.022" and dwell is 28-34 degrees, timing is 6 degrees BTDC.

SN: 3825578 and above uses AC MR43T plugs, gapped at 0.035", point gap is 0.022" and dwell is 28-34 degrees, timing is 6 degrees BTDC."
 
idle for the first one is 500-

idle for the first one is 500-600 RPMs

idle for the second one is 650-700 RPMs
 
"Thanks a lot, PugetSounder. I

"Thanks a lot, PugetSounder. I didn't make the connection, Mr. Obvious. I have an income of less than $1100.00/mo. I spend $350/month on medical insurance and try to do some fishing when I can afford the bait and gas! Just maybe, if you have an extra manual lying around, you could send it to me. Oh, by the way, in California I have to pay about $42.00 a year for my license, so if you want, you could send me some cash too!"
 
"Guy, Thank You for the info,

"Guy, Thank You for the info, now my son has something to work with since this boat out dates him by 30 years and he has never work on an engine 'without smog'. I found the needle valve set screw adjustments in an old Rochester carburetor manual."
 
You have a son...and you are t

You have a son...and you are teaching him all you know
that warms my heart
 
"You have a son...and you

"You have a son...and you are teaching him all you know that warms my heart"

Too bad it's mostly his attitude.
 
"PugetSounder, Thanks, I reall

"PugetSounder, Thanks, I really think we could be friends, let's BE friends, Sorry about the attitude thing. Maybe we can swap fishing tales. email me and lets have some fun! Ron. < [email protected] >"
 
"Hy_Stat, He's a pretty go

"Hy_Stat, He's a pretty good 'shade tree mechanic' he is in the US Army as an equipment maintainence Tech E-6. He could teach me more than I could teach him."
 
"No problem Ronald apology acc

"No problem Ronald apology accepted.

I'm not saying boating should be a rich man's sport but as we all know here it is an expense and can be expensive. Trust me, my boat is 27 years old and whenever I see people on the lake with a brand new version of mine that cost them anywhere from $30K -$40K I think how foolish. But to each his own, I can't afford that much so I bought a good used one with the plan to do my own work.

Buying a $25-$30 manual and having a bit of mechanical experience can be the least expensive way of owning and having fun in a boat. We all have them. Good luck."
 
Wiser words were never spoken!

Wiser words were never spoken! Can you tell me where I might find some place with an assortment of manuals for the older boats? Mine is a 1968 Silver Liner 17' Rambler
 
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