1975 stinger 75hp , 78 sea nymph v, 150psi all 3, only 30mph WHAT? 13 3/4 x15 p,HELP

[phillnjack]

ok here is a 60hp triple fishing motor with a 13.5x15 bog standard alloy prop.
my boat is much heavier and not a great shape for speed at all.
but with this you can see what to expect for the holeshot with your propeller at the moment.
a 13x19 should get you 40mph on your own in the boat, and high 30's with 2 people.
anyway look at this vide to get an idea of a 15 pitch pull away.
this prop gives a top speed of 35mph at 6,000 rpm, on longshaft engine with 2.42 gearing.
if you want same holeshot with more top end speed , then get a 13x19 and drill vent holes in the hub.


https://www.youtube.com/watch?v=nh9GCaU41l8

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[25XS]

You answered your own question. Who runs a stinger on a pontoon?

Fast engines on a pontoon happens A LOT. Look what I got off a pontoon last fall ! I have seen a whole bunch of 75hp Stingers & Hustler longshaft engines on pontoons

1975 Evinrude Hustler 75hp 15" with Nitro gearcase!

[perfmarine1]

If that came off a pontoon with that prop, it will need tore down to clean the carbon cus it didn't rev up enough to burn the fuel. Probably why it's for sale and on a skid!

[EMDSAPMGR]

Getting the engine setup correct is the first place to start your engine tuning. The engine cannot be set too low on the transom, or it will create a lot of drag and will spray a lot of water. Make sure your engine is set to the right set of holes on the transom. When water flows from under the boat when you are planning- the water must completely flow under the engine's anti-ventilation plate-just above the prop. If that plate is dragging UNDER the water (even just a little,) your speed will be down and you'll have a lot of spray. also poor fuel economy.

[staylor]

For reference I ran the same basic 16 ft Sea Nymph many years back with an 80 Merc 4 cylinder on it....I think it was a 1980-1981. I ran a stock Merc aluminum prop and the motor was not raised. Top speed with just me in the boat was 43-44 mph.
Doug

[phillnjack]

WRONG ........ stinger or hustler dont mean a thing about gear ratios. they were all the same.. you got a 75hp longshaft its 20 inch and its 2.42 ratio........ that dont matter if its 60, 65 70 or 75 hp......... now you can get a shorty 15 inch in either 1.86 ratio small gearcase or large gearcase 2.42 ratio..... but saying a stinger is a different ratio is completely wrong... stingers and hustlers came in both 15 inch and 20 inch and are no different at all to any other motor of same hp for same years.. its purely paint and decals... evinrude also done the blue and white livery for the 2 cylinder Sizzlers and the v4 stranglers................you are confusing shortshaft with longshaft.

[phillnjack]

sharpeye mike . porting is not different on the 20 inch powerhead to the 15 inch powerhead... they are identical blocks. if its 75hp then its 75 hp same pistons same everything inc carbs...

[H2OPERF]

Agree it should be a little faster but looking at the pics it doesn't appear too light... with all those interior boxes, console and carpet, is it all wood? plus everything looks a bit foreward, Take a pic of the gear case and back of the boat.

[sharpeye Mike]

sharpeye mike . porting is not different on the 20 inch powerhead to the 15 inch powerhead... they are identical blocks. if its 75hp then its 75 hp same pistons same everything inc carbs...

Sorry. I meant the 75 HP 49 cube, compared to the & 70 horse 49

[Capt.Insane-o]

Cool story bro
..4 years later.

[phillnjack]

some story need to be kept alive... especially now while people can still get some fun.

[sharpeye Mike]

I've got the last year they made them. Johnson Formula E and the Evinrude Sprint. Both of them are short shafts with the nitro gear case. I'm going to hang on to them for a long, long time. In fact, I'm running the Johnson on a Delta

[Revenge22]

just going back to basics here: Are you 100% sure the timer base isn't hung up on a wire or sticking? are the carb throttle butterflys exactly horizontal at wide open? the little roll pins on the carbs should all be exactly vertical wide open.stuff a toothpick in the top one to accentuate the pin, remove the throttle cable and adjust the highspeed stop screw if not.
as mentioned, the 75's were absolute dogs out of the hole. not sure why dealers sold these to anyone accept those with light, fast hulls TBH. More $ i assume. The "regular" 49 cube 70hp is a beast out of the hole compared to the 75's, and that ain't saying much ha. The 56 cube motors... forget it. way more power. You should swap the motor for a 56ci down the road. will be much happier in the long run IMHO.

[sharpeye Mike]

I like what you posted Revenge 22. That's exactly true. My 49 70 horse pushed my 17 footer at 48 miles an hour. I never had a long shaft 75 but played around with several shorties 75s. My Delta went 62 mpl with a 75 HP. A few years ago, I put a 56 cube power head on my SS and now she runs 68 all day long

[Revenge22]

sweet! yeah i've rebuilt many of the 3 cyl but the 92' and on ones were the strongest. oval port i guess they called them. i assume this was an attempt to catch the Yamaha 70hp, and by extension the Suzukis as they were both rockets. i had a rebuilt 75hp 1980 model on a 15' whaler. before that i had rebuilt an 82' 70hp and sold it. well, i thought i had screwed something up during the rebuild on the 75, or a throttle plate was bent it was so slow! hilarious, at my expense. imagine me cursing the 75, beer in hand, trying to figure out what the heck was going on during a summer heat wave. top speed was exactly the same as the 70hp: 42mph and change. said screw it and "fixed" the issue with a crossflow V4. No more wondering were the power went i can tell you that !