Used Engine Question (25 Nissan)

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
Hey guys, just picked up this engine. It's my father-in-laws and I'm hoping to get it running, fix it up, the usual up-keep. But I need some info on it first. I've attached a couple pictures of the tags. Any info such as 2 or 4-stroke, best type of gas, oil/gas mixture, best plugs, etc etc to use would be awesome.

Also, any background info on this line of engines, history, the good, the bad and the ugly. The guts of the engine and block look immaculate. It looks like it's never been run. I haven't tried starting it yet because the gas tank / gas hose aren't compatible. I need to adapt the fittings.

Anyways, any additional info you can throw out there on this thing would be much appreciated.

Thanks in advance.





Scott
 

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pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
That's the last series of 25 hp 2-stroke sold in North America. Somewhere around '02, Tohatsu went with 4-strokes for EPA emissions reasons.
Parts are readily available; I would recommend OEM parts from your local Tohatsu/Nissan dealer. They will also have the correct fuel line connectors. We usually run the BP series of spark plugs (BPR7HS or BPR7HS-10 pre-gapped to 1.0 mm). The P is for projected tip, which stays cleaner longer. If the water pump has not been serviced, it sould be a good idea to install a fresh wp kit (not just the impeller).
All Tohatsu pre-mix 2-stroke motors call for 50:1 fuel/oil mix (as indicated on your emissions tag). Pump gas is OK, but non-ethanol 89 or higher is preferred.
You can up the output to 30 hp by changing the carb base gasket (remove the restrictor), and verifying ignition advance. The 25 and 30 C3's are identical motors. They are very durable motors, difficult to kill.
 

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
Hey Paul, thanks for the update and reply. I took it out of the shed a few days ago, mounted it on my kicker bracket and hooked it up to a new gas tank, fuel hose and fresh gas. Threw some ear muffs on it and after 6-7 pulls it fired up no problem. It chugged a little, and smoked for a few minutes while it cleared itself out, but for the most part it ran great. It's a great little engine and I can't wait to get it out on the water for some fishing.

I'll check the plugs, impeller and water pump shortly. The fuel line has a unique fuel nipple to the engine, a clip-on type deal. Never seen those before. Makes sense as I don't have to remove the hose from the tank, but the engine instead, and then fill it up however possible. Not a bad set up.

How are these things on gas you think? Is regular 89 octane okay, or should I go a bit higher? What about oil? What suggestions for 2-stroke oil would you have?

Appreciate the help.
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
The Tohatsu quick-connects (both engine end and tank end) are pretty reliable -- sort of like an air hose connector. The tank and motor end are different sizes, so you can't accidentally put the primer hose on backwards.

Figure that as you get to WOT, you will burn at least 3 gph, especially if you convert to 30 hp. They are pretty easy on fuel below half throttle.

Any TC-W3 oil is fine.

89 is a lot better than 87, and should run OK. Try for non-ethanol if you can get it, and if you will not be using the motor for more than a couple of days, either run the carb out, or drain it, to reduce fuel varnishing in the carb.
 

NFA

Petty Officer 2nd Class
Joined
Nov 26, 2003
Messages
158
Great ideas. Thanks again. I'm going to run it once more tomorrow I think, check the plugs and a few other things, and then put it away for a couple months. Should I put some fuel stabilizer in the gas tank and get it through the lines when I run it?
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
Great ideas. Thanks again. I'm going to run it once more tomorrow I think, check the plugs and a few other things, and then put it away for a couple months. Should I put some fuel stabilizer in the gas tank and get it through the lines when I run it?
You could. Again, if you drain all the fuel from the internal lines, pump and carb bowl, it's a non-issue. Stabilizer stops rotting of fuel, but does nothing to make it cleaner or leave fewer deposits when it evaporates out of the carb (clogging the jets and passages).
 
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