the ole switcheroo?

[kembry]

Currently I have a 1974 500 50hp Mercury that I posted questions about over a year ago. I was unable to fix what seemed to be a fuel related problem with the motor, and talked myself into taking it to a local mechanic that is said to be very good with old mercs. 13 months later he still has not gotten to it. Lately I've thought about picking it up and starting over on it myself with the help of others on this site. Today I found a 1978 85hp Mercury for sale. I'm waiting on more detailed specs but "compression is good, has a new distributor and new kit in fuel pump". I'm told that the lower unit has recently been rebuilt. This motor was pulled off the boat recently and was running.

My Question is: Will this motor be similar enough to mine as far as controls, transom mounting that it would be worth a shot? For a few hundred bucks are there many important parts that I could rob from the 78 to fit the 74 to get one of them running?

My thinking is that for the price of this motor it might be worth it becuase I'm sure my bill from the mechanic would be more, even if he is unable to fix it.

thanks for the help..

 

[jimmbo]

Re: the ole switcheroo?

The controls will hook up, if the 85 has power trim, that will have to be addressed. 1978 engines still used the electrical harness connector on the starboard side of the engine, so that should be just a plug in operation too.

As for robbing parts off an 85hp to use on a 50hp, not a lot of parts will swap. Perhaps the distributor, but not much elese.

 

[kembry]

Re: the ole switcheroo?

Thanks for the reply jimmbo

The way I see it is for the price at which I can purchase this 78' 85 hp motor, I could possibly get it running before the other one. It's also something else I can tinker with as a learning experience. My boat is rated for a maximum hp of 75. How concerned should I be about the hp rating and weight difference between the 74' 50hp and 78' 85hp? Does any body have an idea how much more the 85hp will weigh? Is either motor more reliable than the other?

Thanks

 

[jimmbo]

Re: the ole switcheroo?

Looking in my 1978 Mercury brochure, there is no such thing as an 78 85hp. The last year for the 85 was 77. Anyways they weigh the same 244lbs. The 50 hp weighs 168lbs

Both engine have their design roots in the 1950s and are very reliable

 

[kembry]

Re: the ole switcheroo?

the guy told me that the 77 has power trim, my 74 does not. Is this going to pose a problem? I don't mind manually adjusting the motor if that can be done. Will the 77 have to have controls in order for me to raise the motor for transit? I talked with him again today, no title for the motor, has power trim, was on a boat less than 3 months ago running with no obvious problems. Is it worth a couple hundred bucks?

 

[emckelvy]

Re: the ole switcheroo?

I can't address the title issue 'cause we don't do silly things like that to motors here in the Sunny (!) Pacific North West!

But I can tell you that if they're asking only $200 for the complete motor, the parts alone are worth way more than that!!!

Just go on eBay and see what a power trim & tilt setup goes for. Not to mention what they're asking for lower units and electronics parts.

However, no matter how little you're spending, you're looking for a running motor so I'd try and run it somehow. You should be able to hook up your 50 hp controls (since you say it had a new distributor, it's old enough that your control harness will be 100 percent compatible), a flusher, battery, fuel supply, and fire it off.

Re: the power trim, it'd be very easy to build a wiring harness to run this, with a 3-position toggle switch, and mount in the dash or somewhere convenient. You don't have to have a factory switch in the control box.

BTW, make sure the pump and hoses go with the setup or it's gonna be really expensive to get those items new or used. And if I recall, you can turn a relief valve on the pump unit in order to manually lift the motor up for transit, but you won't be able to lower it for operation. So you really need the whole setup operational in order to run the motor.

HTH & G'luck.......ed

 

[kembry]

Re: the ole switcheroo?

Thanks for the reply emcelvy. Hopefully my seloc manual will show me some pictures of the pump and hoses you're talking about. I've been itching to get on the water for about two years now since I got the boat, so I needed some guidance to make sure my I was thinking straight.

Thanks again

 

[emckelvy]

Re: the ole switcheroo?

Each power trim ram has 2 hoses attached. So you've got 4 hoses running inside the boat to a small pump.

The hoses are supposed to be routed thru a 4-holed "entry plate" which is usually mounted in the backsplash of the motor well, but I've seen lots of 'em that just run thru the same hole as the steering cable.

Anyway, if you don't see the hoses coming off the motor, you ain't got 'em. If you price these PT&T setups on eBay, they're quite expensive and that's all used stuff.

New hoses are very $$pendy and I don't think you can even get new pumps anymore. So definitely better if it has all that stuff!

Here's a link to a PT&T auction on eBay so you'll have an idea of what to look for.........ed

http://cgi.ebay.com/ebaymotors/1978...ryZ50439QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

(note just to avoid confusion, in this auction the seller has the entire transom bracket that the PT&T cylinders mount to in the picture. The hoses, cylinders, and pump are clearly visible in the larger pic.....ed)

 

[kembry]

Re: the ole switcheroo?

Thanks for the help emckelvy. Now that I have a better idea I'll call the guy and ask him.