Minimum hp for Dolphin 20

[cerealdiet]

Hi, owners/experts. I'm in infrequent poster with more questions than answers, and on my second old Grady. I love these old hulls (plus the only ones I can afford). This time have a 1978 Dolphin I likely need to repower. It's rated for 210 hp, I think. Has an old Merc 150 on it now. I'm definitely looking to buy used--a 90's vintage 2 stroke. I don't need speed, happy to cruise around at 20 knots. Mostly interested in saving gas. Generally will not have a boat full of gear and people. Found a Johnson OceanRunner 115hp I could get for about $1000. Has anyone run a Dolphin or Grady of this size/weight with a 115? Thanks.

 

[gw204]

What's wrong with the Merc that's on there now? If it's one of the old 2.0 liter 150 V6s, run that sucker into the ground and then rebuild it. The power to weight ratio on those motors was excellent and they were very easy on gas.

If it's toast....have it rebuilt.

I have one on my old 204 and at 3600 RPM, it only burnt like 6.5 gal.hr. :shock:

 

[seasick]

My initial feeling is thet the 115 is underpowered for the vessel. As mentioned by GW204, whay not run the Merc?

 

[Grog]

If the Merc runs, run it into the ground. If you're looking to save $, buying a newer motor isn't going to help. A direct injection 2 stroke or 4 stroke (watch the weight) will save on the gas bill but how many gallons do you have to burn to save $10000?

 

[cerealdiet]

Thanks for the replies. The guy I bought boat from said the Merc caught fire and that's why he's selling it. He was quoted $1500-$2000 to repair, but don't know how accurate that is. It's a 1978 Merc, I think referred to as the Tower of Power, straight 6.

I opened the cowl and really it "just" looks like some of the wires are toast and some of the insulation around cowl. He put the fire out pretty quickly. If it was going to be $1500 to repair, why not buy a 1996 Johnson in great shape for less than that? I thought. I was going to take Merc into the garage and tinker with it this winter, but don't know how successful I'll be. Maybe new wires and fuel line and I'll be okay (?). End of season price on Johnson is tempting.

 

[seasick]

It's crazy to spend that money on a 30 year old motor. Nevertheless, I would be hesitant to go with the 115. I still think its underpowered.

 

[ScottM]

cerealdiet,
I have a '78 Overnighter with an early 80's 115hp Evinrude. While I consider it underpowered, it moves along happily at 22 knots and runs 25 in the corner. I'm not going to win any races but that's about all the speed I'd run at even if I had a 200.