Whats the gap on the spark plug for a 83 omc 3.8 gm

Garry69

Recruit
Joined
Jan 10, 2021
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4
What's the gap on the spark plug for a83omc3.8 liter gm and what wood b the oil I wood use for that engine thanks for the help I need it I'm a new boat owner and first time doing all that I need to do in the spring so just won't to do right and change oil and new plugs and filter and gas filter so thanks again for some help
 

bruceb58

Supreme Mariner
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Mar 5, 2006
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0.035

Check dwell and timing as well. Replace the points if you don't know how old they are.

Dwell is 36° ±2°
Timing 10° BTDC
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,798
For oil you can use straight 30, 15w/40, 20/50, or Merc’s 25/40. Just not the lighter weight automotive oils like 5/30 or 10/30, these may thin out during high rpm marine use.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
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47,296
first, welcome aboard.

since you already bought the boat, we cant talk you out of the purchase

being a 1983, its a stringer 800 drive. they were obsolete when the drive was new.

just in drive service, plan $1000. you most likely need ball gears, raw water pump with housing and you need to inspect the 3-piece vertical drive shaft. you will need to do the work yourself or find a grey-beard retired OMC technician that may do work on the side

you will need a factory manual. the only place to get a factory manual is here: https://www.outboardbooks.com/

there are 3 gear boxes in the drive

does the tilt motor and clutch pack work? if not, you will need to replace the tilt motor and do not take the clutch pack apart without the required tools

inspect your boot

do not damage the lower shift cable. they are now $850

the trim pump and system is obsolete, however there are companies that you can get replacements.

if you have the bat-wing exhaust manifolds, plan on changing them

inspect the stringers and transom for rot. boats over 15 years of age have issues, yours is coming up to 38 years
 

Garry69

Recruit
Joined
Jan 10, 2021
Messages
4
Thanks very much for all advise and your telling me that my boat is a stinger 800 and one more question what oil filter wood I use for this boat and is there a gas and water repeater if so what kind wood I get to replace it I just got the boat and havingreally looked in the motor I'm just getting thing now for in the spring . Hope these questions are not to dummy I don't no **** about these motors just learning about them as I go so really need the help so thanks again
 

Garry69

Recruit
Joined
Jan 10, 2021
Messages
4
And what's the gear oil numbers I looked it up but asking so I no it's right have looked up lots of stuff but just not sure so need second opinion
 
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