overpowering danger?

[Azlo]

What can happen if you overpower? I have a 68 starcraft with a 4 cyl merc (140hp). I am wondering if i can install a v8. I know the hid tag says 170 limit.
But what dangers are there when you over power?

 

[futz]

Re: overpowering danger?

want more power go with a inline six. but how fast you going now, i bet that boat being so light flies.

 

[HT32BSX115]

Re: overpowering danger?

There could be a danger.


In the extreme, you could break the transom or engine mounts. or you could get it going so fast that you would lose control etc.


It's unlikely though. Many I/O boats were rated up to about 300 (crankshaft) hp.

My previous boat (1966 18' Mark Twain) came with a 110, 120, 150 (Mercruiser #1 drive) and 190, or 310hp(#2 drive) Mercruisers. (The placard indicated max HP 310)

If you're smart enough to have insurance, and you do lose control and kill someone, your insurance company could actually refuse to pay a claim since you knowingly modified your boat in violation of accepted practice & USCG regs etc.

This is sort of like installing automotive parts on a boat and then having a "Kaboom" event.....

An insurance company might not pay in that event and if someone dies, the other parties family (lawyer) will take everything you have it they can prove to a jury that you were "at fault".

You WOULD probably be at fault if you disregarded the placard (ABYC and USCG accepted practices) and installed more HP than is recommended safe....


Of course anyone can sue anyone else....I for one wouldn't try to make it easier.


Your mileage may vary.


Cheers,


Rick

 

[wca_tim]

Re: overpowering danger?

depending on what year, my understanding is that a lot of boats had max horsepower determined strictly based on hull length...

on my 17 foot the coast gaurd tag doesn't list a horsepower, but I believe it is something like 185 on the manufacturers speci.. I'm well over double that and the boat handles great, has great manners, etc... Note that I picked the hull because they're overbuilt and I knew I was going to "oever power" it.and I added strength to the engine mount and especially transom area (for an i/o almost all of the torque load on the hull is at the transom, the front engine mounts mainly need to be able to support the weight...

and by the way, to swap to a v-8 you'll need pretty much everything except for the transom assembly. have to build and glass in engine mounts and supporting structure underneath, and all the engine parts including exhaust. not trying to dissuade you if you want to do it, just understand that it's probably a minimum $4-5k job that'll include a significant investment of time and energy as well... in this economy you could buy another boat with a 350 in it that's ready to run or one heck of a fast eggbeater boat...

 

[Azlo]

Re: overpowering danger?

Thanks Guys, I really appreciate the comments. I love the sound of that v8. Maybe I can hot rod my 4 cyl, 1 thing i am gonna do is drill holes in the transom to add exhaust outlets. Any body has hot roded their 4 cyl. Or should add a inline six like Futz says. I didnt know there could be so much legalities (thanks HT32BSX115). Man I dont know what to do

 

[Bondo]

Re: overpowering danger?

Man I dont know what to do

Ayuh,.... Trade Up,.... Your Plan is Full of Holes......Pun intended....

 

[dubs283]

Re: overpowering danger?

Maybe I can hot rod my 4 cyl

spend your money on a new boat with a V-8

 

[wca_tim]

Re: overpowering danger?

I agree!!!! keep the 4banger, and either sell it or keep it when you "upgrade". if you want to go boating instead of fiberglassing, grinding, mixing and matching parts, looking for things you forgot about or didn't think about needing, etc...

 

[futz]

Re: overpowering danger?

first that ain't no 140 if original. might not be 120. could be a 110.

second i rethought the 6 suggestion i gave you i would leave it alone and enjoy it the way it is if it runs well.

Want more hp get a boat with the motor and drive you want in it.

Just to involved to go from say a 4 to a 8.
And to hopping up, the 4 banger forget it ain't gonna happen.

 

[Azlo]

Re: overpowering danger?

U right Futz, i dont think its the original either. The valve cover says 140 and when i looked up the carb serial for a kit, its from a 1973 engine.