225II-TR or 255II-TR
 

Does anyone know how to quickly tell the difference between a Mercruiser 225II-TR and a 255II-TR drive without the serial numbers that apparently no longer exist? I have a Mercruiser Operation and Maintenance manual that came with my boat, but I'm not sure which I have. Ultimately I need to replace my drive so I need to know what parts to look for. Unfortunately I can't link pictures to this thread since I can't upload them to my Google Drive while on my work network. :-(

Thanks all!
-Dave

The tr is most likely a 2:1 ratio and can take a 20 inch diameter prop. The trs is 1.5:1 and will take around a 15 inch diameter prop. I believe the uppers are the same.

if thats what your asking

Hmmm... the plot thickens I suppose. I believe the prop on mine is roughly 18" across. In a call with Mercruiser based on the model year of the boat, the motor and transmission in the boat with serial numbers, they believed it was a 1.5:1 ratio.

When I get home I'll get some pictures of this thing posted up so everyone can get a visual.

If its got an 18 diameter prop its not a trs

I'm pretty confident it's a TR based on the manual I have for it. Just not sure if it is a 225 or 255. :-(

Anyone know where I could find a replacement drive? Essentially the entire thing from skeg to transom mount.

put a wrench on the prop nut. if it is 1-1/16ths, it is a TRS. if bigger, it is a TR. overpriced, but cases look good. make him an offer. only so many people looking for houseboat drives... https://www.ebay.com/itm/Counter-Rot...RY-O82&vxp=mtr why do you need whole drive? cases shot?

Those are #3's

What is a 3? Besides a speedmaster 3? In which case they are not overpriced.

Really old school (late 60's). Essentially a 3 SSM upper with a houseboat lower.

Genuine Mercury & Mercruiser parts. III 1968-1972 - 2373127 THRU 3002613

Check Cincinnati craigslist.there is one for $1200.

So, I sent the guy on eBay a message telling him what I'm pretty sure he has. Not pretty sure it's not like van has no idea what he's selling. Anyway, are those Speedmaster 3 uppers worth anything? I assume his $7,000 price for the two drives is more than those two uppers are worth? Obviously, he didn't pay anything for them since he does not know what they are. He stumbled across them and stuck them up on eBay for expensive.

I believe the numbers you are talking about are referring to the engine, not the drive. Send me some pics of it and I'll try to identify it for you and let you know what your in for. [email protected]

What year and kind of boat and what engine?

I'm pretty sure the shaft is over an inch so I'm thinking it'll be bigger than 1 1/16th but I can verify.

Yeah, it's got some cracking and holes on it and just looks like a problem waiting to happen.

It's a 1973 Gibson 36' Houseboat. I'll email you a few pictures. I don't have 10 posts on here yet so it won't let me put URL's or pictures.

Funny you mention that. I've already been talking to the guy about it actually. The design though is slightly different on the upper portion.

UPDATE: The TR advertised on the Cincinnati Craigslist apparently isn't an actual TR. It is believed to be a III drive.