470 merc 170 hp i/o convert to outboard

[fmalott]

I have a 1983 thundercraft with a 470 merc cruiser 170hp the motor runs well right now but in time it will have to rebuilt or replaced. i was talking to this person from Newfounland Canada his life is boats they say when these types of motor blow they convert to a outboard motor they reinforce the transome so it can hold a outboard motor has anyone did this or has seen this conversion so my queston is is it cheaper to rebuild the 470 or convert to outboard? the boat itself is in excellent shape worth putting another motor in or outboard motor in

 

[Bondo]

Re: 470 merc 170 hp i/o convert to outboard

so my queston is is it cheaper to rebuild the 470 or convert to outboard?

Ayuh,... In my experince, most hulls don't take nicely to moving all that weight aft...

Not that it's a Easy swap by any means,...
But,...
Swapping in a 4.3l is by far the most efficient swap to do...

 

[fmalott]

Re: 470 merc 170 hp i/o convert to outboard

what would be the best motor to replace the 470 another 470 or different motor that would hook up to the alpha 1

 

[Lyle29464]

Re: 470 merc 170 hp i/o convert to outboard

That is a problem with the 470's nothing inside the boat will work. so except for the outdrive unit you replace every thing and even the prop.

 

[fmalott]

Re: 470 merc 170 hp i/o convert to outboard

so i'm stuck with rebuilding a 470

 

[NYBo]

Re: 470 merc 170 hp i/o convert to outboard

All the more reason to be meticulous with preventative maintenance to forestall that dreaded day as long as possible.

But Bond-o suggested a 4.3L V6. The difficult depends a lot on the layout and dimensions of the engine compartment and stringers..

 

[444]

Re: 470 merc 170 hp i/o convert to outboard

Anything can be adapted, whether or not it's worth it is the question. Look at some boats where basically the same hull is offered in i/o and ob. Buying a good, used OB is not exactly cheap either so rebuilding what you have or converting to a 4.3 of 5.7 is probably your best bang for your buck if you're mechanically inclined.

 

[fmalott]

Re: 470 merc 170 hp i/o convert to outboard

there is not a problem on being mechanically inclined i'm very new to inboards i have been an outboard person for so long rebuilding or replacing is no problem i just don't know what's better when the old motor finally dies rebuild a 470 or replace with different motor i know there is alot of negitive opinions on the 470 but i'm sure if it's well looked after you will get a number of years i'm not looking for speed just cruising

 

[roscoe]

Re: 470 merc 170 hp i/o convert to outboard

Watch these youtube videos of i/o to outboard conversions.

It can be done, and as seen in the first video, less power, less weight, same performance.

http://www.youtube.com/watch?v=t0KeS5M5TCM


http://www.youtube.com/watch?v=_Wr4XRfi-5M&feature=related

 

[tschmidty]

Re: 470 merc 170 hp i/o convert to outboard

Yes it can be done. I'd personally rework the transom rather than use a bracket but it is more work. It's not so much a matter of weight but weight distribution. With a lighter outboard you can get away with a bracket or somesuch.

Still easier to sway a 4.3 or something I would think but others can speak more knowledgably about that.

Just maintain the 470 and cross that bridge when you get there.

 

[QC]

Re: 470 merc 170 hp i/o convert to outboard

Moved this over to non-Repair I/O as we try and keep the boat section free of engine topics. This one is kind of on the border, but I felt it was better here.

 

[Don S]

Re: 470 merc 170 hp i/o convert to outboard

so i'm stuck with rebuilding a 470

FROM YOUR ORIGINAL POST: I have a 1983 thundercraft with a 470 merc cruiser 170hp the motor runs well right now but in time it will have to rebuilt or replaced.

Why don't you just sell it now while it still works, and buy something you can deal with and don't have to re-design?
With the money you get from the running boat, and the money you would have to spend for either an engine rebuild, or a transom and outboard, I would imagine you can find something you like fairly easy.
Or is there something I am missing and you have a reason you must keep this particular boat?

 

[fmalott]

Re: 470 merc 170 hp i/o convert to outboard

i just bought the boat last year and just wondering on the best thing to do Don S. i'm kind of a vintage rebuilder for snowmobiles and outboard motors now i want to have a inboard i put all my vintage snowmobiles away now it's boat time the 470 runs great right now i put a alternater kit on it already. i'm just preparing myself for the future when motor needs replacing also the boat itself is in excellent condition that's why i bought it

 

[Don S]

Re: 470 merc 170 hp i/o convert to outboard

Since it runs good now, with proper care and preventive maintenance, that motor will easily last for 10 more years at minimum.

 

[Bondo]

Re: 470 merc 170 hp i/o convert to outboard

i'm just preparing myself for the future when motor needs replacing

Ayuh,... Like I said, the 4.3l is the least painful, most logical option...

 

[stonyloam]

Re: 470 merc 170 hp i/o convert to outboard

Look at it this way: There are only 3 major drawbacks to the 470. The alternator takes care of one. The cam seals will eventually have to be replaced and they are prone to blowing head gaskets, so you have to keep an eye on the temperature and engine compression. It was designed as a marine engine, so the bottom end seems to be at least as strong or stronger than the other 4 cylinder engines, and it is light, powerful and economical. Blown head gasket or replace seals? Start working on it after breakfast on Saturday, and you will be able to take the boat out for lunch on Sunday. One major advantage is that if you want to use it late in the season you can drain the exchanger in 3 minutes right on the launch ramp and never have to worry about a cracked block. I agree with Don.

 

[fmalott]

Re: 470 merc 170 hp i/o convert to outboard

i looked at some video on converting to outboard seems like more work then rebuilding so i guess i will just keep my eyes on the motor and hopefully i will get some years out of it and when motor does need rebuilding i think i will stick with not converting i tell you one thing there lots to learn

 

[stonyloam]

Re: 470 merc 170 hp i/o convert to outboard

IMHO that is a wise decision. There are a couple of things to do this spring. You should do a compression check and a cooling system pressure test. You can get the tools for both from the Autozone free tool lending program. Those tests will tell you the current condition of your engine, and now is a good time to fix any problems. While up to temperature and running on muffs, look for any coolant leakage from the weep hole on the engine circulating pump (cam seals), make sure the weep hole is not plugged. Change the impeller to make sure you have good seawater flow through the exchanger. Oh yeah, don't forget to retorque the gimbal ring clamping bolts on the outdrive (55 foot pounds) a pet peeve of mine. I think you might just conclude that it is not such a bad thing to be in the "470 club". Good luck.