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Discussion Starter · #1 ·
Does anyone have a PDF copy of a service manual they'd be willing to email me for a 1999 Mercury Sea Pro. My SN starts with 0G80. Just picked it up on a whim and don't even know if it runs, but it'll be a good time trying to make it work. I have no idea what size the 3 blade prop is because the numbers are all messed up. It says (corroded)38 X 13P. What's normal for this size motor?
Also, does anyone have any tips for me about this motor. Any insight is appreciated.
 

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Discussion Starter · #4 ·
Here are some images of the inside of my 25 Sea Pro (1st) then side shots of a 25 or 30 Tohatsu I use to have.  The 25 Sea Pro resembles all other small Mercury motors I've had over the years that ranged in the 1990's.  The Tohatsu looks a lot different.  I've read comments on a few sites where people say they are the same motor and if I need parts for them to shop Tohatsu parts, but after looking at the motors side by side I don't think they're the same.

Here are the images: 
Sea Pro:




Tohatsu:


 

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The top motor is Mercury, not Hatsu and parts are readily available at any Merc parts dealer. The shop manual link I posted is for that motor. Have fun getting her running. If compression and the gear case are good, the rest should be cake. :cool:
 

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Discussion Starter · #7 ·
I cleaned the Carb yesterday which was nastier than any carb I'd ever cleaned. I ordered some parts through boats.net which haven't arrived, so I put it all back together with what I had.  I changed the gear oil and took it out in the river for a test.  The motor took some time starting. Not sure, but the weather may have had something to do with that. Temps were in the 50's here when I was starting it.  It would start, but would die quickly there after. I had to keep it revved up for a while before it would stay running. 
It ran in Fwd and Rev at slow speeds just fine and when I ran at WOT it would lose power then regain power and so on. I figure that is because of the messed up diaphragms in the fuel pump.   
It doesn't seem to like to sit at idle, but I've read that may be normal for them. I may mess around with the screws around the carb to see if I can get it to idle better, or does anyone have any suggestions about this? 

 

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Rebuild the carb, new fuel filter and spark plugs before anything else. Make sure your fuel lines and primer bulb are in good shape, with no leaks. All that is inexpensive and it'll potentially run a lot better.

Merc 2-strokes do tend to idle rough, but keep in mind that the knob on the front of your motor is a combination choke and idle adjustment. You pull it to choke the motor. You twist it to adjust the idle. So, once you get the carb set, it's easy to tweak by hand, without removing the cover.
 

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You know what? I take back some of what I said in my last post. I clicked on one of your motor pictures and it took me to your photobucket album. I scrolled through the rest of them and now realize that's a commercial motor, so it's a little different. Still a mercury-made, just small stuff like the carb are different. I've never worked on a commercial motor, so I don't know if the choke/idle knob works the same, it may be choke only. It also looks like the top of the fuel primer assembly is missing. That may be by design on the commercial ones, I just don't know for sure.
 

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Discussion Starter · #10 ·
It is the commercial motor which does not have the little primer and the choke only chokes; does not adjust idle.
On Friday I ordered new plugs, impeller, carb rebuild kit, trim tab, and cowl latch (it was rusty).
I'll run her again once I install all of that stuff.
 

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Never seen this motor.Its not the tohatsu.Looks just like the merc except shifter is on the side and not on the handle.Pretty old motor.If any Merc dealer can get you parts then its Merc.On my 2007 sea pro,Merc dealer can't get me parts.Only tohatsu dealers can.
 

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Discussion Starter · #12 ·
Never seen this motor.Its not the tohatsu.Looks just like the merc except shifter is on the side and not on the handle.Pretty old motor.If any Merc dealer can get you parts then its Merc.On my 2007 sea pro,Merc dealer can't get me parts.Only tohatsu dealers can.
I ordered parts for it on boats.net. Parts should arrive this week. I hope they fit.
 

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Discussion Starter · #14 ·
All my new parts are now installed and carb rebuilt. Took it down to the river and after adjusting the idle screw (I think that's what it's called) the engine runs great and actually idles pretty well.
So for now my blind purchase off of Craigslist turned out to be a success.
 
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