Does anyone know what the difference is between a Mercury/Mariner 2.5hp and 3.3hp motor? Specs on displacement seem to be the same, though lower unit gearing is a little different. Is it possible to up the horsepower of the smaller unit with a larger carb jet, perhaps? Anyone done this with this or similar small outboards?
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Engines
Walt - There are two principle differences. First the smaller engine is geared differently. That's why it can't spin the prop fast enough to get to 3.3 horse. The jet is also different but you don't really need to change it to up the horse power. Second, the smaller engine does not have neutral while the 3.3 does. I have the 3.3 and love it - its actually been dunked twice and works fine anyway. I wouldn't have it without the shifter. Justin - O'day Owners' Web
Walt - There are two principle differences. First the smaller engine is geared differently. That's why it can't spin the prop fast enough to get to 3.3 horse. The jet is also different but you don't really need to change it to up the horse power. Second, the smaller engine does not have neutral while the 3.3 does. I have the 3.3 and love it - its actually been dunked twice and works fine anyway. I wouldn't have it without the shifter. Justin - O'day Owners' Web
Walt: I Was Told Jetting and Propping
by a dealer. I had a 2.5 for years and noe have the 3.X with the neutral shift. FWIW, unlike Justin, I could take or leave the shift. I don't find it any big difference. These are great engines and seem to own the small engine market under one brand or another in SoCal. BTW, check the spec's on thrust. That is the important measure and you may find them very close. RD
by a dealer. I had a 2.5 for years and noe have the 3.X with the neutral shift. FWIW, unlike Justin, I could take or leave the shift. I don't find it any big difference. These are great engines and seem to own the small engine market under one brand or another in SoCal. BTW, check the spec's on thrust. That is the important measure and you may find them very close. RD
difference
Does anyone know what the difference is between a Mercury/Mariner 2.5hp and 3.3hp motor? .8hp (sorry couldn't resist)
Does anyone know what the difference is between a Mercury/Mariner 2.5hp and 3.3hp motor? .8hp (sorry couldn't resist)
A Rose by any other name is .....
I think that they are all built by Nissan/Tohatsu. The different US mfg just have them painted to match the rest of the fleet. I have a Nissan 3.5 with the shift. I would not consider one without it. Carrying it is like a briefcase.
I think that they are all built by Nissan/Tohatsu. The different US mfg just have them painted to match the rest of the fleet. I have a Nissan 3.5 with the shift. I would not consider one without it. Carrying it is like a briefcase.
Air intake blockage
I have read that the only differenceis that they air intake on the 2.5 is partially covered by a piece of plastic, effectively acting as a governor. Remove the plastic and you have the 3.3. I cannot say I have independently verified this, however, as you noted, displacement is the same so makes sense. Just like Intel used to do with the "SX" chips when the deliberately degraded a faster chip solely for the purposes of market segmentation.
I have read that the only differenceis that they air intake on the 2.5 is partially covered by a piece of plastic, effectively acting as a governor. Remove the plastic and you have the 3.3. I cannot say I have independently verified this, however, as you noted, displacement is the same so makes sense. Just like Intel used to do with the "SX" chips when the deliberately degraded a faster chip solely for the purposes of market segmentation.
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