Am I wasting my time and money

[Special K]

I acquired a hydro and motor in good shape for almost nothing. The motor is a standard mark55. I added a header, lighter flywheel and shaved a little off the lower unit. Question is am I wasting my time messing with the regular service motor. It’s mounted pretty high, is that going to throw off the balance ofthe boat and can I really expect any kind of speed from the thing. I’m not a racer just going to mess around down the street in good old Lake Erie.

[Larry M]

For just playing around I think you will have a good time. The lower unit will be the biggest draw back. Yes it is top heavy but going in a straight line I don't think you will have any problems, it would not be good for turning in a race. I think you will see around 55 MPH depending on what props you have.

[Special K]

I have 2 different props. One appears to be a standard fishing prop but the other has a shorter sharper blade. Do they make any better props for an evinrude fastwin? Like to get more speed out of my little runabout.

[ZUL8TR]

I agree should be fun, 55 is fast if not use to it so wear a good safety race type jacket and helmet and have somebody in another boat for helping in case.
If it doesn't have one install a electric cut off tied to you
Do the carbs have full butterflies, they could for safety cut off?
Can your locals stand for the scream from those M - phones, they can be annoying?
Show some pics of the rest of the hydro. Get a bottom width at the transom, boat length and weight if you can manage.
A service lower will go ok for fun if you get the right prop but be careful in the turns as noted by Larry M, things happen very fast when least expecting them.

[MadProps]

Ive done this and for me it WAS a waste, I was looking for 50mph or better for the kids to play around.

you wont even see close 55 mph from that gear foot, fastest props for that motor are not available to get you going any faster and it would be a minimal improvement at best if you could find the steepest pitch, your limited by the props and gearfoot, frankly it doesnt matter what performance enhancements you do to that motor, it cant go any faster than the props available for that gear foot
in comparison to a race motor your motor will rotate 3 times for one rotation of the prop, in comparison most racers are 1:1 or close to
a 30 hp Yamato on that rig will be approx 55-60mph depending on your weight experience etc and there was a Y80 for sale here last week $1300
you will have fun with what you have, you just maybe not be satisfied in short order, if a MK55 motor could possibly run 55mph on a 3 point I would have been satisfied and not have started buying race motors, even the kids got bored quickly

I have a few videos of a couple mk55's on different 3 point hydros if you need proof of concept, believe it or not the sound track in one video is Sammy Hagar " I cant drive 55" when I was looking for help just like you are now

edit: you may want to look for a Mk 55H midsection and gear foot they can be bought in the $1000-1500 range and you will be thrilled

[Special K]

There are no noise ordinances on Lake Erie in my location. They actually hold the power boat races right here in mentor on the lake. Seems like I may very well be wasting time with this service engine. May have to locate a different gear case or maybe another motor if I feel the interest in the boat is big enough. Sure looks fun from watching videos.

[Special K]

1 more picture

[ZUL8TR]

Just for reference when I built the hydro in my avatar all I had at the time to play with was a service Mark 20 with a 2 blade alum prop. I set it up best I could and it ran about 42-43 . Then I picked up a 20H with 1:1 gears and right to the low 60's. When started in APBA racing in '73 and ran the Merc 25ss it was a mid 60's hydro. On the fun side just for grins also ran a friends 35hp Erude on it and water skied behind that hydro, Erude was deep with 3 blade prop so it had pull power but maybe 35mph without the skier.

[Special K]

What do you think of this idea. Looks primitive but functional.

[ZUL8TR]

Those are stick tower units used in the pro class, they work well easy to get the mid section to suit and mate to the Merc powerhead, The gear case is is another matter to get. If a Yamato gear case used they are force fed with prop blast no water pump. Not sure what Yamato gear case used for that 4 cyl Merc. A Merc D gear case will work but $$$$, they are 1:1, and require lot's of good care to keep alive, finding one in great shape will be a chore, you never know what the inside reveals, need a reputable source.

That hull with a stick tower and the right prop will be a very fast boat way over 55 for sure, now you are into serious speed and dangerous as well if not skilled with it..If you go the stick tower route you need to really cut that transom down.

To quote you - "I’m not a racer just going to mess around down the street in good old Lake Erie."

The 55 with Megaphones on a stick tower with a race gear case -set up right would not be a starter setup if not familiar with these boats.

What is the bottom width at the transom, boat length transom to bow and weight if you can manage.

[dwhitford]

That's an Elderdge gear case in the photo, a very good, sturdy gearcase. Do you have one?

[ZUL8TR]

I have no Eldridge gear cases .

[Special K]

The bottom width on the flat underside is 35 inch. From side to side is 47 inch. Boat length looks like 11 feet even. No way of taking a weight but it’s not very heavy. It has 3 gallon tank, even has a 80 mph speedo

[Special K]

It also appears that the transom has been added to to get the height for this motor but was defiantly shorter at one time.

[Special K]

These are the 2 props I got with the motor. The one is definitely a fishing prop. Not sure if the other is any better.

[Larry M]

What I would do is take it out and run it and see what the speed is, right now it is just a guess. I had a FeatherCraft aluminum runabout with a Merc racing unit and it would run almost 60MPH this was with a 44 merc with stacks and no porting. Another guy had a aluminum boat with a 44 and a club foot and it would run almost the same speed.

[Special K]

Very mixed opinions on this whole subject. I’m beginning to think I bit off more than chew with with this project. My original goal was to find a nice 8 foot Hal Kelley or something like a sea flea so my wife could drive my mini speed boat with me. Seems I stumbled on this boat not knowing how complex it was to get the speeds these boats are supposed to reach. I hate to give up so easy but I may restart my search for something obtainable. This is my boat that sparked my interest in the first place. Only get 27mph but that’s all it’s supposed to get.😄😄😄😄