Re-power help: Do I need to limit horse/reduce horse power to be within specs?

[Can'tFishEnough]

OK, I need some advice on a pending repower - I'm not sure if this forum is only for hulls, but this seems like a building/design/restoration thing so if it needs to be moved I can do that.

I ended up with a good deal for a 1979 55hp Evinrude (titled with good compression and an old set of controls) and didn't have to deal with getting rid of or storing an old boat while trying to salvage the motor. I'll be starting a new link as well and will post the url when I get it done - but I still need advice.

I got the 55hp running somewhat by squirting fuel in the carb throats and cleaning off some terminals and setting up a "tiller handle" type circuit to go to the starter solenoid since the engine harness had been set up with truck/trailer style plugs and the controls have a standard big red plug.

So I think I'll get it titled and go ahead and spend the $ on carb kits and new plugs... but my question is how safe is this to run on a boat that is rated for 45 hp tiller motor. Or should I get this one running and sell it and the 25hp that is on there now and try to get a 40 or 45 tiller handle motor? (may be my eventual route anyway if I can actually find a decent used one).

Or do I need to find a way to limit the hp of the motor down some? I don't know if just retarding the timing, or blocking the wide open throttle position/max RPM is good or should I put some sort of restriction between carbs and intake manifold? I know that asking how to loose HP is probable sacrilegious- around here, but that may be where I am to stay safe.


Thanks.
new thread link coming shortly. If you wouldn't mind answering there It would be appreciated.


Specs:
-I don't find any laws against it in TX.
-Boat built in '94 16 ft 9 in Alumacraft V-16 lunker LTD rated for 45hp tiller
-current motor is 1994 25 hp Evinrude with tiller steering. Good for a light load but hard to push more than 2 adults. Current prop is a modified Evinrude prop 11x10 that is at top of RPM when I'm alone and in the middle when 3 adults and around 18-20mph at WOT.
(when I looked up a few '94 model two strokes they were in the 180-190 pound range.)
-Transom is 20 inches from clamp area to bottom of boat (But the clamp area is about 6 inches lower than side gunwales of boat- I think this is somewhat typical)
-Transom width is 68 inches at top (widest part) roughly 60 at water line with a very very shallow V.

-New to me old motor mod# 55975c weighs 187 based on the nadaguide info.
Would be trying to set up boat with a remote steering/control console

I'm curious since I don't really understand the differences between horse power measured at the block like the 79s or the prop like the 94s
I also don't know exactly why tiller handle boats are typically rated lower for max hp than console boats.

I'm not looking for "what if" legal advice - I've read lots about all that on other threads asking about over powering, I'm really looking for practical advice that you'd tell your son who just wanted to go out and be safe on the water with the grandkids... It seems to me that there is a range that changing to older horsepower type rating and to console steering might make the '79 55hp the equivalent of a '94 model 45hp.

Thanks.

 

[jbcurt00]

Stay with in rated capacity specs.

 

[mickyryan]

most of what I saw as citations for boats from uscg was for overloaded capacity or over hp limit when I went through there citation list a while back

 

[Can'tFishEnough]

So that is my question: Is there a way to limit the horsepower so that the 55 hp built in 1979 (where horse power was measured at engine block if I understand correctly) runs equivalent to a 45 hp built in 1994 (where horsepower is measured at the propeller)? There also seems to be some differences based on if the boat was sold with a tiller handle or with remote steering. From what I've been able to figure out the Coast Guard plate isn't a hard and fast rule unless the state that your in or body of water that you're in says they're going to enforce it as such. To the best of my knowledge, Texas has not such laws at least in my area.

I understand that the "appropriate answer is" don't go over, but I'm trying to find a way to either limit the motor so that I don't or make sure that I'm within safe limits based on the hull, transom, and control design- which don't always make a black and white rule when converting from old motors to new or vice versa and between different steering set ups.

 

[jbcurt00]

Only you know if its a problem in your area to overpower.

Nobody will care that a 1970 55hp is (or is not) equivalent to a 1990 45hp if the boat is rated for a 45hp.

FYI, in WV (and at least 2 other states I've looked up for similar posts), overpowering is specifically addressed under the regulations for maintaining control and safe operation, even if overpowering isnt addressed individually.

Remote vs tiller arm
15 vs 20in transom
Length
Beam

Are all figured into the equation for max hp ratings.

Again, stay w in listed limit for max hp.

Didnt you ask for practical advice you'd give your son or grandkids?

 

[ondarvr]

most of what I saw as citations for boats from uscg was for overloaded capacity or over hp limit when I went through there citation list a while back

I would like to see where you found citations for boats being "overpowered", the CG even states in their regs that this is not a law or rule, only a suggestion and is not enforced by them because there is nothing to enforce.

They can cite you for unsafe or negligent boating, but just being overpowered doesn't automatically put you in that category.

I'm not saying it's a good idea or recommending it, just asking to clear up any misunderstandings.


C F E , Tiller boats can be more difficult to control at speed, so the HP limits are lower.

You can get a certified HP reduction kit for a 50HP Evinrude, It might be the same one for the 55, (same basic motor). They were used in Alaska when they had a 35HP rule on the Kenai, it's a 50HP limit now.

 

[mickyryan]

ugh I knew someone would ask lol
, I will see if I can find , it was one night I was searching for capacity info and clicked on something and all the sudden it was cases from like 1995 to present opened and closed in a pdf file , was very interesting read none the less

 

[Can'tFishEnough]

So, I called TX parks and wildlife today and they said that unless the bigger motor obviously affects the handling or safety of the boat they don't care about the plate as it is just a suggestion/recommendation. Which is the same thing they told me in the past about the load rating for # of passengers (unless you're on a jetski/pwc).

ondarvr-- I can't find any kind of "hp reduction kit" available. Any ideas where I might look for something like that?

jbcurt00, "Didnt you ask for practical advice you'd give your son or grandkids?" Yes, I did. And I do appreciate your responses, but like a typical kid, I'd like to ask "why?" is this the only practical solution, and if so, is there a way to "de-power" the 55 by a few horsepower to make it "safe" according to the plate? I'm only being persistent because I've been trying for a long time to find a running (and in Texas it has to be able to be titled) 40-45 hp tiller with no success (or even a 35hp tiller). So finding this motor with paperwork was the closest I've been able to get without shelling out the for a showroom new motor.

by the calculations I found length x transom width (transom height is also 20in) x 2 -90 for remote the boat should be able to go up to at least 85-90hp (which seems a bit extreme)
or by the tiller calculations length x transom x 0.8 -25 it should go to around 50 even for tiller (16.75 x 5.67 x 0.08) -25...

so, this is why it's confusing to me when using an older outboard and possibly a different steering set up why is 45hp still the max?

 

[slimdaddy45]

I dont know for sure but is the 55 and the 45 basically the same motor if so you could put 45 carbs on it to reduce hp maybe just a suggestion or adjust the throttle linkage to where it doesnt open all the way up

 

[ondarvr]

I dont know for sure but is the 55 and the 45 basically the same motor if so you could put 45 carbs on it to reduce hp maybe just a suggestion or adjust the throttle linkage to where it doesnt open all the way up

No, you need a certified modification with the new HP rating for it to be legal if there's actually a rule governing it.

 

[ondarvr]

C F E

They were sold in AK for fishing the Kenai, so check a dealer in Soldotna. There could also be some used kits around because they aren't required anymore.

 

[Scott06]

You mention rules in TX, I thought this kind of stuff was encouraged down there... Get a decal kit for a same manufacturer with lower hp put them on the engine and use your head when opening it up . Don't do anything stupid and you will be left alone. All kinds if resto quality decals available.

When I was 13 I put my grandfathers 9.5 evinrude (still have and runs great) on a 12 ft aluminum boat he got my cousins and myself rated for 6 hp, and I'm still hooked and fast boats to this day....

 

[Can'tFishEnough]

You mention rules in TX, I thought this kind of stuff was encouraged down there... Get a decal kit for a same manufacturer with lower hp put them on the engine and use your head when opening it up . Don't do anything stupid and you will be left alone. All kinds if resto quality decals available.

When I was 13 I put my grandfathers 9.5 evinrude (still have and runs great) on a 12 ft aluminum boat he got my cousins and myself rated for 6 hp, and I'm still hooked and fast boats to this day....

Well in some circles, yeah, probably encouraged But not "on the record".

I just want to be able to not buy a new boat to try to pull kids around as they get a little bigger, and want to be able to be able to get 2-3 guys on the boat at a time and be able to get across some of the larger lakes around in a decent amount of time. The weight to available horsepower ratio with the 25 I have drops off pretty quick when trying to get out of the rain or in some of the windy choppy conditions on some of the lakes I'm on often. I mean I like speed also, but have a lower tolerance for the edge of your seat adrenaline rush than I use to though my grandfather never let me drive (I think his 12ft was actually rated for a 9.9 but I was too young to pay attention to what motor he had on it- best guess something around max.) It would cruise with the two of us on it- but boats on the water always seem faster than when I'm in the truck pulling it. all about perspective I guess.

Mod EDIT

I like the space in the boat that a tiller allows, but think that putting a makeshift handle on a 55 might be asking for trouble.

 

[Can'tFishEnough]

C F E

They were sold in AK for fishing the Kenai, so check a dealer in Soldotna. There could also be some used kits around because they aren't required anymore.

I'm not sure google has made its way to Alaska yet I'll see if I can look a little more specifically for some dealers and email them directly .

thanks!

 

[ondarvr]

Just about any of the tiller handles off of an OMC motor will fit, the throttle cable is the only thing you need to match up, but most cables can be made to work.

 

[Can'tFishEnough]

YGet a decal kit for a same manufacturer with lower hp put them on the engine and use your head when opening it up .

would probably just paint the whole thing without the #s before spending more for false advertising It's scratched up enough at this point it could use some paint on the leg and cowling both.

 

[Can'tFishEnough]

I dont know for sure but is the 55 and the 45 basically the same motor if so you could put 45 carbs on it to reduce hp maybe just a suggestion or adjust the throttle linkage to where it doesnt open all the way up

not sure about the 45... I'm under the impression with my limited knowledge on the subject that the 25 pwr head is the same for 20 to 35, and I know the 50 and 55 are the same prw head, but I don't if the 50/55 one is the same for 45 or even for the 60+... I think there was a 40 and 45 that might match and 60-70 might. I'll have to learn some more.

 

[Corjen1]

Here is my perspective, for what its worth...HP ratings are targeted at WoT (wide open throttle). ie 55 HP at xxx rpm. Also, a HP rating is a general assumption.. meaning the rating is developed at the factory under specific atmospheric conditions, over an average of performance parameters. Its also a de-rated number that builds a safety factor for the manufacture.

You also touched on an important variable in the quote/unquote safety discussion.... in the late 60's/early 70's, they change HP ratings from crank HP to prop shaft HP. ie a 1965, 100HP motor is the exact same (or close) as a 1995 85 hp motor in the actual horsepower applied to the prop....that translates to a specific and equal force applied to the transom.

That being said, how often will you be running at Wot? Quick burst, or sustained rpm and speed? Do you normally run at 1/2 or 3/4 throttle.... (27.5 or 41.5 HP) Both are well within the " safety" plate on your boat. Mathematically, you can justify the numbers. Is it safe... in my humble opinion absolutely.

Here is a different side of the coin I think you should consider... from an insurance/accident/lawsuit perspective. God forbid, you had an accident and severely injured someone. How do you think the courts would way in on the case after the plaintiffs attorney has shown your willful intent to overpower the vessel, that had clearly defined and stated HP ratings? Do you think the Insurance company would still pay out on a lawsuit?

So....is it safe...most likely yes. Is it reasonable/justifiable? Im not pushing any pro or con. all Im saying is that only you can make that call... your boat, your decision to accept the risk or not.

Good luck in your decision sir.

 

[Can'tFishEnough]

Here is my perspective, for what its worth...HP ratings are targeted at WoT (wide open throttle). ie 55 HP at xxx rpm. Also, a HP rating is a general assumption.. meaning the rating is developed at the factory under specific atmospheric conditions, over an average of performance parameters. Its also a de-rated number that builds a safety factor for the manufacture.

You also touched on an important variable in the quote/unquote safety discussion.... in the late 60's/early 70's, they change HP ratings from crank HP to prop shaft HP. ie a 1965, 100HP motor is the exact same (or close) as a 1995 85 hp motor in the actual horsepower applied to the prop....that translates to a specific and equal force applied to the transom.

That being said, how often will you be running at Wot? Quick burst, or sustained rpm and speed? Do you normally run at 1/2 or 3/4 throttle.... (27.5 or 41.5 HP) Both are well within the " safety" plate on your boat. Mathematically, you can justify the numbers. Is it safe... in my humble opinion absolutely.

Here is a different side of the coin I think you should consider... from an insurance/accident/lawsuit perspective. God forbid, you had an accident and severely injured someone. How do you think the courts would way in on the case after the plaintiffs attorney has shown your willful intent to overpower the vessel, that had clearly defined and stated HP ratings? Do you think the Insurance company would still pay out on a lawsuit?

So....is it safe...most likely yes. Is it reasonable/justifiable? Im not pushing any pro or con. all Im saying is that only you can make that call... your boat, your decision to accept the risk or not.

Good luck in your decision sir.

thanks- that is sort of why I was asking about how to "de-power" it a touch. With the 25 hp we're WOT almost all the time. It's loud and still doesn't get anywhere very fast with a moderate payload weight according to the plate. I'm hoping that I can use this one at half or 3/4 throttle and still have better performance (and maybe even similar gas consumption) than the 25 on there now at WOT. I guess, as you and others have pointed out in other forums and posts, I need to check into the insurance aspect and see how that would work.

 

[ondarvr]

Let's get back to actual results and not theoretical insurance claims.

Agents that have posted on here say that claims are paid when the boats are overpowered, they didn't know of any that had been denied. They also said if they didn't cover stupid or potentially illegal accidents that they would issue far fewer checks.

Again, I'm not recommending overpowering, only keeping the statements accurate.