it works !!! Now i want it faster...............

jordan23 · Mar 12, 2013

Finally got my 84 70 hp johnson seahorse to run perfect.....any tips on making the engine faster...any props that anyone might have in mind ,for top speed......spark plugs ,electronics etc..............thanks much.

RogersJetboat454 · Mar 12, 2013

Re: it works !!! Now i want it faster...............

What's your wide open throttle RPM?
May get a LITTLE speed by optimizing the prop (if there is some to gain).

The best spark plug for that engine is what OMC recommended.
"Electronics" aren't going to offer any improvements either.

bonz_d · Mar 12, 2013

Re: it works !!! Now i want it faster...............

Lighter boat. Not much can be done to hotrod an outboard.. Trim right and correct prop's about best you can do,

nwcove · Mar 12, 2013

Re: it works !!! Now i want it faster...............

The old adage is....."to go faster add lightness".

BonairII · Mar 12, 2013

Re: it works !!! Now i want it faster...............

Propping correctly will give a good balance of speed/holeshot.

Find out what your motors optimum rpm range is(probably stamped somewhere on your motor)....and choose a prop that will get you to the top of that range at WOT.

JB · Mar 12, 2013

Re: it works !!! Now i want it faster...............

The most performance gain can be found in fine tuning prop, weight distribution and height and trim of the outboard. Modifying the engine is a waste of money.

Chinewalker · Mar 12, 2013

Re: it works !!! Now i want it faster...............

Actually, most performance gain is gotten by unbolting existing motor and replacing with larger motor...

bonz_d · Mar 12, 2013

Re: it works !!! Now i want it faster...............

So long as exsisting motor is not already at max for boat.

Roberthill · Mar 12, 2013

Re: it works !!! Now i want it faster...............

Mill the head??????????

jordan23 · Mar 13, 2013

Re: it works !!! Now i want it faster...............

The wide open throttle rpm is at 4500 . Where it says it should be.. Got ac delco marine which is the recommd plugs.... Thanks man will look at a new prop then....much apprctd

jordan23 · Mar 13, 2013

Re: it works !!! Now i want it faster...............

Got 16 ft alumm. 1959 cherokee ski boat ,three seat and a steering wheel lol. light as i can get it..........

jordan23 · Mar 13, 2013

Re: it works !!! Now i want it faster...............

70 hp on a 16ft alumm boat is enough on the back i think...

Chinewalker · Mar 13, 2013

Re: it works !!! Now i want it faster...............

jordan23 said:
The wide open throttle rpm is at 4500 . Where it says it should be.. Got ac delco marine which is the recommd plugs.... Thanks man will look at a new prop then....much apprctd

Not exactly. Your motor's recommended operating range is 4500-5500. Ideally, you want to prop it to the top of that range. If your motor is peaking at the bottom of the range, then you are lugging the motor and not making full power. If it were mine, I'd probably even aim for a hundred or two above the peak, with a light load, so that when you've got friends and gear onboard you're pulling into the upper end of the range...

jordan23 · Mar 18, 2013

Re: it works !!! Now i want it faster...............

The engine could of been farther down in the water ..I had it set at the second notch.. Would that make a difference in rmp? Have a total of five settings i think. Prob should of been at 3..... P.S Can u explain for a dummy ,exactly what u mean by , hundred or two above the peak , so I can tweek her...Thank you sir ..............................:joyous:

Chinewalker · Mar 18, 2013

Re: it works !!! Now i want it faster...............

100 or 200 RPM over the 5500 top end, so aim for 5600 or so while you're prop testing.

Motor angle is a trade-off, that's why they invented power trim. Try them all, but don't be surprised if you wind right back up where you started (at #2 hole). You may find you're faster on top end at hole #4, but it blows out in turns or on acceleration, or it porpoises at cruising speed, etc. With power trim, you can alter for conditions and loads at the touch of a button...

fishfeatures · Mar 18, 2013

Re: it works !!! Now i want it faster...............

get a jack plate, jack up the motor and get it setback so you can get that gearcase out of as much water as possible. Get a water pressure gauge installed too, so you don't do damage to the motor.

V153 · Mar 18, 2013

Re: it works !!! Now i want it faster...............

I'd start with motor height. If the anti-vent plate is equal to or lower than the keel? That's too low.

You just might get your revs up into range by raising the motor a hole or two. Then start monkeyin around with props.

Sadly without power trim the process is hit or miss.

jordan23 · Mar 19, 2013

Re: it works !!! Now i want it faster...............

Gotcha ,have a power trim for dat engine ,but its in a box in my closet lol.... Thanks for all the great advice guys, will work on getting the power trim on it.....Another adventure !!!!!!!!!!!!!!!!!!!!!!:facepalm:

JB · Mar 19, 2013

Re: it works !!! Now i want it faster...............

jordan23 said:
The wide open throttle rpm is at 4500 . Where it says it should be.. Got ac delco marine which is the recommd plugs.... Thanks man will look at a new prop then....much apprctd

I don't think so. Should be Champions.

jordan23 · Mar 21, 2013

Re: it works !!! Now i want it faster...............

Sorry your right,have marine champions in there. ac delco my cadillac lol.............................................:facepalm:

it works !!! Now i want it faster...............

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