Merc500 on D Housing ?

[mk30h]

Guys,
I would like to know if a white 62 Merc 500 will fit on a D housing? It's a jet prop model with the old rounded style lower cowling. The attached picture shows the bolt pattern.
Thanks
Steve

[Thomas H]

Should work just fine. I used to run a Mark 58A (same powerhead as your 500) on a Mark 55 lower unit, and the Mark 55 was the basis powerhead used on the Mark 55H. The Mark 55 H used the D lower unit you are refering to. You'll have a little less RPM, lots more torque. Have fun!

[150aintenuff]

should work fine... as should any 50 HP merc built into atleast '72

[Mark75H]

should work fine... as should any 50 HP merc built into atleast '72
No, not as late as '72; some time in the mid 1960's the back two studs changed. Many lazy assemblers just pull out the back 2 studs out and only use the front 6 studs.

The 1962 powerhead will fit all 8 studs.

[2us70]

I think it is a straight drop on but I don't remember if the exhaust tuner will fit in a D mid section.

[Mark75H]

I think it is a straight drop on but I don't remember if the exhaust tuner will fit in a D mid section.The tuner will not fit in a D tower

[alanaker]

The exhaust tuner as is (not shown) will not fit into a D midsection. However, if you trim approx. 2" off the bottom it does fit into the D tower. Works nicely. The motor shown uses the rectangular shaped tuner which is angled forward. I always thought that the later bolt pattern with the two rear studs moved back 1/2" was the 1965 model year. 1965 and later uses the round style tuner which points straight down.

[150aintenuff]

No, not as late as '72; some time in the mid 1960's the back two studs changed. Many lazy assemblers just pull out the back 2 studs out and only use the front 6 studs.

The 1962 powerhead will fit all 8 studs.



LERN summthin everyday.... I was told they were the same till 72.... my bad...

[2us70]

I think the studs were changed when they changed to the rubber mounted and suspended cowlings. I do know it was a lot harder to mount a steering bar to the later motors. The bar just bolted up to the bottom pan on those old white motors. My first race motor was a 62 500.

[Dave S]

Came when they went to rubber mounts on the cowl and the new power dome combustion chamber in 1965. The Dome gave a longer block so the rear bolts had to be moved back. ;)

[Dave S]

Sorry I did not read the thread above. :o :rolleyes:

[mk30h]

Thanks guys, you solved my problem. I had a mk55h with a blown upper cyl. have a couple of mark35a blocks but think a 44 cu inc may be a better bet parts wise. Have a merc 400, but it is complete, and the 500 merc is parted.
Winter project.
Steve :)

[150aintenuff]

the merc 400 and 500 are DARN NEAR IDENTICAL so if ya do have aproblem with the 400 at some piont you could use it on it as well....... ALSO if ya need a spare mota I have one I no longer have a boat for.. would sell it for the right price:)