1986 Mercruiser 165 same as 1973 MC 165 Drive?

[marvinjansen]

I have a 1973 Aristocraft 19 with a Mercruiser 165 that needs an upper drive. Mine broke some gear teeth. Will a 1986 MC 165 drive be the same and fit? I can get a 1986 Stingray ski boat with a MC 165 real cheap for parts if it will fit. It is about a 100 miles from home and I wanted to ask before heading that far.

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

No, the 1973 is called a MC-1, the 1986 is called an Alpha 1 Gen 1. They physically interchange with no issues, you just need to make certain to use a alpha one gasket.

The 1973 165HP is an inline 6 and will have a 1.65:1 gear set.

The 1986 165HP is a 470 4cyl inline and will have a 1.84:1 gear set.

They are a direct bolt on swap either way you go, but the gears will be mismatched. The gears that determine the ratio are in the UPPER unit. The lower units do not matter in gearing.

The mismatch in gears can be corrected by changing props, but it will never be "optimal" or perfect. But will certainly keep you on the water having fun until you can get the proper ratio. I would think if you increase one prop pitch you would be ok. Like 19 pitch to 20.

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

What is "real cheap" If it runs and has lots of good parts, the 470 engine is worth it if you have the ability to strip and part it out. And most importantly have a place to dispose of a boat afterwards.

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

the guy telling me about his neighbors boat said it was a straight 6 cylinder but he may be wrong. I striped an older 140hp last month but the drive shows alot of wear on the gears and is really a wrong ratio at 1.98 I think. I do have a place where I scrapped the hull and motor for about $30, not too bad.
From what you are saying, the drive should bolt on with a different gasket?

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

If the 1.98 drive off the 4cyl is acceptable, bump up 4 pitch sizes. You were more than likley running a 19p. Bump up to a 23p. Or if using a 17p, goto a 21p.

They did not make an inline 6 past 1980. Unfortunatly.

If you get the alpha 1 gasket, it is backwards compatible to older years, it just sticks out and looks ugly.

 

[stonyloam]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

The parts off of the 86 470 engine should be worth at least a couple of hundred dollars.

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

Talked again to neighbor of boat owner, says it definitely had a straight 6 cylinder and must be older Stingray boat. Now it is an 1980 or older right? May be able to get it for $200 or so.

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

Probably worth the 200 in parts if there is good parts. Thats what you will need to find out. I got a free boat with a I6 but the block has an external crack. Thankfully the rest of the engine was perfect. I had a place to junk the hull for free as well. I really made out with a bunch of good parts.

What area are you located?

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

I am in Tuscaloosa, Alabama

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

Too far...... I had a nextra I could have loaned ya, but I actually can;t sell it. I am running one now that leaks a bit and I am just lazy to change it out. It was a freebie so I am not complaining.

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

I put a new double seal in the lower I am using now. I was able to remove the 2 old seals with a dent puller and screw. I would like to get tools and know how to take the drive upper and lower apart. Do you rebuild yours or swap like I have been doing?

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

I just swap the units. I have cobbed some together good uppers/lowers. I have a total of 4 extra drives ranging from 1.65:1 up to 1.98:1

The one I run now on my glastron, requires a little fluid each time I take it out. I just use the cheap automotive stuff and let it leak a bit. Too lazy to swap it again. It is the lower that leaks.

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

Owner contacted me and it is a 4 cylinder so wrong ratio for MC 165. I did install the 1.98 upper I salvaged and it is very noisey but did work last weekend. Found my WOT increased from about 3900 to 4200 and seemed to have to run 3500rpm to get the speed I had at 3000 with the 1.65 ratio. Wife says we need ear plugs now.

 

[Fordiesel69]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

What speeds are you showing at those RPMS? Seems overpropped if you can only get 4200 with a 1.98 drive. Are you running a 21p prop?

How is it out of the hole?

Keep and eye on the lube level. Keep the drive alive until you can find a proper upper. BTW, how is the lower unit on the noisey drive? Does it leak?

 

[ziggy]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

don't know if this will help or not.
wot spec is 3900-4300rpm. so @ 4200 your close.

my boat (same as yours) tends to have a speed that's almost same as the tach. like. at 4300rpm's speed is 42-43 mph. at 3500, speed is 35 mph. etc. this is generally true (for me) down to about 2100-2200, which is where i plane at. 2000rpm and i'm still plowing. 2100 and i'll come up on plane.

i run a 19p aluminum flotorqueII prop.

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

Didn't have a speedometer, just went by feel. Definitely lower speed for same rpm. Pitch prop is 19. Good out of hole. Lower unit is good, I put new seals on prop shaft.
I may go look at the 86 with 4 cylinder and see what that drive looks like. He wants $500 for Boat, and trailer, too much but will take offers.
Are you sure the '86 drive will just slide into my '73 bell housing? Will the shaft be a longer one and maybe I'll have to swap drive shafts?

 

[marvinjansen]

Re: 1986 Mercruiser 165 same as 1973 MC 165 Drive?

My MC165 on the Aristocraft 19, same as your Ziggy, rpm equaled the speed with the 1.65 upper and original p19 prop. This 1.98 upper lowers top speed. I like the 1.65. Have an adjustable prop and may try it on 21.