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20 HP Mercury 200

C

crazyhorse357

Member
"Hi Folks,
I am new to this f

"Hi Folks,
I am new to this forum and fairly new to boating. I recently bought a used 14 ft Jon boat with a 20HP Mercury engine, I have never put it in the water, however I did have the seller connect a water hose to the pickup and it cranked and ran fine impeller was 'peeing' as it should, my question is what would you folks recommend doing to this motor before putting it in the water and trusting it to get me back to the trailer?
Many thanks,
crazyhorse357"
 
"Put an impeller in. Just cau

"Put an impeller in. Just cause the Tell Tale works with a water hose providing the flow, it won't necessarily pump on its own.

I'd buy a new set of plugs, install them, and keep the others a spares.

Drain and refill the gear case. Look for water coming out and--if so--plan on a resealing job in the near future (and keep the LU out of the water when not using it).

If it idles okay, swell. If not, you might need to rebuild the carb.

Jeff

PS: That's a great little;e motor."
 
"Totally agree with Jeff.

A

"Totally agree with Jeff.

Any motor that is "new to you", you have to assume that all the routine maint is way out of date, no matter what "some guy" told you.

My experience has been that very very few used motors are sold because they are "perfect".

Think about it, if you had the "perfect motor" would you sell it????"
 
"Thanks Jeff & Graham,
Yo

"Thanks Jeff & Graham,
You both have been a great help, I will do as advised, and I agree with you Graham, I would never sell the "perfect" motor, I am sure that it is old, however it cranks easily (electric start) and seems to run fine. but prevention is the key to enjoyable boating, not having to deal with it while on the lake, right?
Thanks again,
Frank"
 
"The guy at the parts store sa

"The guy at the parts store said I will need the serial number to buy parts for my engine, also said it would be on a plate somewhere on the engine, problem is I can't seem to locate the plate, can somone point me in the right direction and bare in mind I don't know all the lingo used in outboards, so you might have to draw me a picture, so to speak.
Many thanks,
Frank"
 
"Hi,on the earlier mercurys,th

"Hi,on the earlier mercurys,the serial number was on the transom bracket[the bracket that clamps to the back of the boat]at the front,between and above the clamp screws,should be something like 3226958.its also on the intake manifold housing,on the RHS[looking from the front],just below the flywheel,you should see it stamped in,horizontally,on a flat piece"
 
"Thanks Mr Summerville,
I wil

"Thanks Mr Summerville,
I will check the places that you described and see if the number is there, and if I can find it I will but you a steak."
 
"Frank, yes, this is an awesom

"Frank, yes, this is an awesome little motor with ton's of potential.

They usually only die from lack of regular maint.

So give it a really good "once over" and then treat her good and it could well last another 20 or 30 years...."
 
"Thanks for the vote of confid

"Thanks for the vote of confidence Graham,
I will begin to tinker with it when the weather warms up some, at least I now know where to turn if I should get in a bind.
Thanks for everyone's assistance
Frank"
 
"That motor also has plenty of

"That motor also has plenty of performance potential. I modified the one with an exhaust divider and a bigger carb, and the little sucker pushed my little boat as fast as a Merc 25 (also with a bigger carb). That's not supposed to be the case, for the Merc 25 is a looper design.

Jeff"
 
"The 20 really is a great litt

"The 20 really is a great little motor. One of the first (small) Merc's to get the Thunderbolt 4 ignition (1973 models on).

Absolutely the only thing I don't like about the design was the reeds on that donut at the base of the crank which means splitting the block if they have an issue - but otherwise, a really tough motor to kill..."
 
"Agreed, and it's kinda ha

"Agreed, and it's kinda hard to work on the carb with that dopey wall of aluminum in the way.

On the internal reeds--that Merc clung to long after there was a better way.... I modified an old Merc 350 twin over the winter to use external reeds. I'm dying to see how well this little 30 cuber will go.

Jeff

376065.jpg
"
 
"Well Jeff,
If looks are an i

"Well Jeff,
If looks are an indicator, it might just sprout wings, BTW, my motor appears to be missing a piece of the engine cowling, right in the center where the latches are, apparently where the "Mercury" logo was displayed, you would happen to know of a good parts link for these old engines would you cause I think I am going to need some more stuff as well cause when turning the lever from idle to wide open it feels like it is binding and very hard to turn until it gets to a certain point and then it flops over to wide open."
 
"Thank you Graham, I will give

"Thank you Graham, I will give them a try, you don't happen to have relatives in Mississippi do you? The reason I ask is a friend of mine, Charles Lamb, recently passed away.
Frank"
 
"Hey Y'all,
I managed to

"Hey Y'all,
I managed to locate the engine serial number on the intake manifold, however I can't seem to make heads nor tails out of the chart that gives the year model, would it be too much trouble for someone to that the time to check it for me, I can't see too well but I am sure I got the correct number cause I took a magnifying glass out there with me.
If one of you guys would look it up for me I sure would appreciate it and I will try to do better in the future. BTW, it is a 20hp/ electric start and the number is 4957540.
Thanks very much,
Frank"
 
"You are quite welcome - and t

"You are quite welcome - and to answer your earlier question "no", the flock of Lamb's that I belong to immigrated from England about 100 years back and all settled in Ontario and New Brunswick here in Canada..."
 
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