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  1. jimmbo

    Am I under proped?

    Props may state the same Diameter and Pitch, but often are like Apples and Oranges. 200rpm over the WOT range, isn't instant Death for the Engine, but it might affect overall Longevity, though less than Over-propping would
  2. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    Butchery, that is all it is. I doubt it even adds 1/10 mph
  3. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    So the Exhaust now also comes out the Water Discharge Drains just above the AV Plate, which will also dump more water into the lower Exhaust Passage. Backyard Butchery
  4. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    Nitrous would increase the Power(Torque) at any Rpm that is utilized at. But at Rpms above the Spec Range, the Port Timing will still restrict Induction, and the Power will still be Lower than what the Peak would be. Likely Melt the powerhead too...
  5. jimmbo

    Help Getting Boat on EZLoader Trailer

    Perhaps some Air in the Trim System. Check the Service Manual regarding Bleeding. On some, but not all, designs, just running the Pump after the Unit is at the Stops, was the way to purge Air
  6. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    Spinning it faster than the Recommended WOT Rpm Range, will result is a Horsepower Drop, unless the Port Timing, Induction and Exhaust are modified.
  7. jimmbo

    Help Getting Boat on EZLoader Trailer

    I can't speak for what Racer does, but I drive my Boat on to the Bunk Trailer, yrs ago when I had the Roller Trailer, I always used the Winch. Backing in too deep and you will have many problems trying to get the Boat Centered on the Trailer. I used to sit at the Launch just for the...
  8. jimmbo

    Help Getting Boat on EZLoader Trailer

    This how far/deep I usually back my Bunk EZLoader in, but I have loaded it with the Trailer about 4 feet forward My Roller EZLoader never had to go in any further than this
  9. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    looks like a 20" to me The Serial # should be on a disk, that looks sort of like Frost Plug on the Engine Block. Looks like a late 80s/early 90s
  10. jimmbo

    A prop question (enertia or other versus older props)

    I have been running an Enertia since 2006. It is a very good Prop, and it has a Tenacious Grip on the Water. Your Boat will likely ride Higher out of the Water, the entire Boat, not just the Bow. However a 15X15 is probably not enough Pitch. Your old AL Prop, was it cupped? The SS you put on...
  11. jimmbo

    383535 vs 311932

    While the 18/20 hp shared the same displacement as the 25 in 69, they had different Pistons, Crankshafts, Carb, and as you know Cylinder Heads, The 25 Head has a smaller Combustion Chamber, to restore the Compression that the 25's Pistons reduced. Putting a 20hp Head on a 25 will really drop the...
  12. jimmbo

    No sparking v4

    1966 - 1968? 1971, 1972? 1978 - 1980? These are just some of the years that there was a 100hp, and all are different.
  13. jimmbo

    Prop Help

    85+% of Boaters have No Clue about Rake and Cup, what they are or what they do.
  14. jimmbo

    Gas - Oil Mixture on old Evinrudes outboards

    Yes, I have watched People meticulously measure the Proper amount of oil, fill the tank, pour the Oil in, put the Cap on, start the Motor and go... Contrary to what the Oil Makers say about easy mixing, it isn't self mixing.
  15. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    That was an interesting Read about the Development of the Merc V6. I remember reading how they made a V12, by placing 2 V6s kind of facing each other
  16. jimmbo

    Gas - Oil Mixture on old Evinrudes outboards

    If the Bearings are Well Lubed at the Specified Gas-Oil Ratio, more Oil doesn't make them Run Smoother. 16:1 was used prior to the Mid 50s. Some Engines, like the British Seagull, used a 12:1 or a 10:1, even in the 70s. They were Great for keep Mosquitos at bey Most engines from the 70s can...
  17. jimmbo

    Gas - Oil Mixture on old Evinrudes outboards

    OMC started using the Single Fuel Hose as Standard Equip on the High End Motors(some 35s and the V4s in 1958), though it had been offered in the Accessory Book for a few years, so the engines could be used on Boats with Large Fuel Tanks. From 1957, on, the Big Twins and V4s all had Antifriction...
  18. jimmbo

    How to choose an old 2-stroke 150/175 Merc

    The XR were Rated at the HP on the Decal. There is a 15% tolerance, but the main Difference between, an example, the Reg 150hp and an 150 XR2 is the Torque Curve of the Power Band. The XR2 had Beefier Midrange Torque, this was the result of different Exhaust Tuning and possibly slight changes to...
  19. jimmbo

    Replaced carbs in four stroke outboard - now hear popping

    On a 2 stroke, it was easy, as the Carbs had to be fully closed at Idle, and the Linkages between them could be set. Do you have the Factory Service Manual for that Engine? If not, get one
  20. jimmbo

    Prop Help

    Looking at the pic, it looks like a 15"(short) shaft motor
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