Is a 73 merc 200 interchangable with a 77'??

[fbnewbie]

I was going to buy it as a parts motor, didn't think it was a 73 cause it looks just like the 77<br /><br />Can I switch out the parts (except for the powerhead?

 

[Chinewalker]

Re: Is a 73 merc 200 interchangable with a 77'??

Hi FBNewbie,<br /> Some parts are interchangeable, but not all. Ignition components are completely different, as the '77 has the "plastic" powerpack, while the '73 is either a "low tension" magneto, or a "metal" powerpack motor. I don't recall which, but it is different and not interchangeable. Powerheads are about 80% interchangeable (different upper cap, different crankshafts). Gearfeet are interchangeable. '73 may have been the last year of the Tillotson based carburetor, or it may have been the first year of the MerCarb - I don't remember off the top of my head. <br /> I've done a lot of work on the 1970s 20hp models and they changed a LOT of little things from year to year - enough to make it VERY annoying when trying to mix and match...<br />- Scott

 

[fbnewbie]

Re: Is a 73 merc 200 interchangable with a 77'??

I mostly want to switch lu components and the complete exhaust housing from the 73 to the 77. The motor on the 77 is pretty good. <br /><br />That is if I ever get the LU off the 77 (different post!!!)<br /><br />I don't want to buy the 73 and get a bunch more headaches

 

[Chinewalker]

Re: Is a 73 merc 200 interchangable with a 77'??

Hi Fbnewbie,<br /> I am fairly sure that most of the lower unit stuff had been standardized by '73. Along about 1970 or 1971 they changed the shift pattern and related tilt-lock linkage, which makes for some headaches, but I think you'll be okay with the '73. One thing to look for on the '73 are the carbon steel shafts are prone to rusting, particularly below the waterpump housing. I don't think Mercury went to stainless shafts until about 1976, maybe even later....<br />- Scott

 

[fbnewbie]

Re: Is a 73 merc 200 interchangable with a 77'??

Thanks so much!!<br /><br />Do you know if the exhaust housing (leg??) will change out also?