none racer needs advice!

[minispeedtoth]

I just joined the forum and need a little advice from the experts. I'm not a racer but I come from a Mercury background, my father has built a few race boats for people so I have a little idea on these boats and motors, my dad has a vast mercury and antique outboard motor collection.. Anyways on to my question, I recently bought a mini toth speed boat for a run around rig, it came with a 20hp Johnson, motor works great but my father told me about the 25xs and the 44xs Mercurys, he said there great engines. wheres the best place to buy them? any companys rebuild them and sell them?

heres my little runabout


and the Campion decals are removed now

[Yellowjacket]

Both of those motors are based on the "fishing" motors. This means that they were basically the stock fishing powerhead mounted on a racing lower unit. From that standpoint you can make a racing powerhead out of a fishing powehead with some work to blueprint the ports and open the rod clearances. That gets you the powerhead, but that's not really the problem.

Both of these motors are getting expensive to keep up. The reason is the lower units are what makes them special and these are getting hard to find and are expensive to rebuild. In addition they aren't robust, and don't seal well. As a result they need to be serviced with almost every use and they need frequent repair.

Sorry to say that because they would save a good bit of weight and would make you boat a lot of fun and a lot faster. If you were to buy a 44xs today it would cost on the order of $4,000 for a decent one and you would spend most of your time tearing down and relubing the lower unit after every weekends running. Even the older Mark 55H and 58H engines are going for around $3,000 and they use basically the same lower unit.

It would probably make more sense to find a used older Yamato race engine since some of them are obsolete now, and they are a lot more usable for a lake racer.

[minispeedtoth]

perfect info!! thank you so much!

[3autility]

25xs

I think the transom on your boat is probably too tall for the short 25XS motor.

[Mark Monkres]

There may be some guys here that could make your OMC run, foot, tower, prop.
.02

[ZUL8TR]

Yamato Engine

One to look into is the yamato 302 (33hp) CD ignition, plenty of parts, lots of advice on this site and they are presently used in lots of race classes around the USA and Europe. They are relatively easy to get. .

Don't know where you are located but here is one source in the Seattle Wash. area

Rick Montoya
http://www.yamatoracing.net/

There are others.

These engines also appear for sale on this site.

For less money there are still Yamato Y80's (30hp)around and Yamato 102's 33hp), both point ignition. Both are still raced today.

props would need to fit your setup.

[mkotwicki]

Form what I see your Laker 2 seat boat is made for a fishing motor. Stick with what you have and get yourself a jack plate with power trim. Make sure your water pick up is always in the warer. You can frog around with the settings as you drive electronically running alone or with a passenger. Shoot a roostertail whenever. You can also get yourself a Cleaver and Chopper prop and tweak your ride between a hole shot vs top speed. Get a Tach and speedometer as well. Get some fins if you don't like the way it turns. Get a windshield. Yada,yada all good. Fun looking boat.

[johnsonm50]

Its a neat looking boat, the 20-OMC definite underpower tho. There's alot that can be done w/an OMC. The gearfoot can be improved but is far short of a race gearfoot. Prop choice also is limited to slow & slower unless you adapt some righty speed prop.



This lower is an OMC that is locked in forward, the reverse gear teeth are removed & the cone is epoxy. It has made 52 gps on a vintage hydro, 46 on a vintage runabout. The prop is 13.5 P.

Otherwise to really go fast w/an OMC it needs alot more & alot less.



Ive done alot of work there because I wanted to see how far one could go..still looking. I agree with Z about a 302 or some Yamato at least. Bolt on speed & good reliability at an affordable price. The mercs are amazing in that some still race dominantly today but the upkeep is potentially high.
When you do get to 40-50 or more be careful, run it thru its paces gradually aware that it could have a suprise reaction or 2 in store for you to figure out. Knowing speed & RPM + keeping notes will help. Before you pour $$$ into it I'd suggest working with what you have, try props, adjust weight & its distibution. Check the bottom to be sure its straight & speedworthy. Change the motor setup around & see what happens. [watch cooling] usually a motor like that will suffer prop traction loss before cooling problems but those OMC's can't handle heat very well. Most of all Good Luck & have fun.

[Dave M]

302

An issue you might want to consider when looking into the use of a 302 Yamato is water. These engines are for racing, and they do not pump water with the traditional water pump. You can't putt with them, they need to be ran on plane to pump water, or just off plane in some cases. I think you are better off working with some of the OMC's with fishing gearboxes as they pump water and you can shift. Makes it nice when playing around by yourself on a lake. You can make a 35hp OMC produce a lot of HP. You options are wide open, depending on how far your pocket book will take you.

[minispeedtoth]

thanks a lot for the info guys!,, I was considering cutting down the transom some to adapt a shorter lower unit, but I like the idea of a jack plate, I might decide to look for a 40 hp Merc. I really appreciate all the useful info, to be honest my main goal is to get into the high 40's low 50's mph range and shoot a nice rooster tail! lol

[johnsonm50]

thanks a lot for the info guys!,, I was considering cutting down the transom some to adapt a shorter lower unit, but I like the idea of a jack plate, I might decide to look for a 40 hp Merc. I really appreciate all the useful info, to be honest my main goal is to get into the high 40's low 50's mph range and shoot a nice rooster tail! lol

Evinrude 25 rooster, its a later 31.8ci version, the older 22's can be fast but don't have near the torque which is more desirable in a fun boat. 40-45 +? is obtainable with a good prop.. see Boatracingfacts GT Pro's using the Evinrude/Johnson's. As far as a fun boat a Yamato would be fun but does have limits of use.

[John drawe]

i just got a 1977 25 Evinrude. Twice as fast as the sea king 15! My question is, will a 35 HP carb add 10 HP to my 25?

[ZUL8TR]

carb and hp

i just got a 1977 25 Evinrude. Twice as fast as the sea king 15! My question is, will a 35 HP carb add 10 HP to my 25?

Not knowing the internals of the 25 vs the 35 I doubt it. It might make it run worse.

[runabout333]

The motor on the 28J boat... Is that what AOF is calling the B-1 Bomber??
Just curious... Not interested in one.

[minispeedtoth]

if I can get my little 20 to perform like one of those motors would be great, I only paid $500 Canadian for the boat and motor.. I'm reading that the 35hp carb & intake will bolt on as long as its the same model year.. what else can I do? I love the look of the big pipes and the chopper blades and race style lower unit... theres so much to learn about these motors