Merc 1000 / advice

[MF67]

Hi, my buddy has this Merc 1000 rated at 100hp.
He thinks its a 1968, but not sure?
How can we properly date it?

How many rpm's do you recommend running it at, etc?
He replaced the bottom and is running a #19 pitch prop.
50:1 fuel mix ratio.

Any comments or advice about this operating/servicing this motor will be aprreciated.

Thank You

 

[79Merc80]

Re: Merc 1000 / advice

Hello:

From the looks of it, it's a 1968/1969. Looks good. I believe the Max RPM should be 5000 - 5500, but they love running at about 4200. Others will chime in with more accuratwe information.

Have fun with it.

Craig

 

[emckelvy]

Re: Merc 1000 / advice

Yup, '68 or '69 depending on Ser #. Advertised WOT range is 4800-5300 but it ain't gonna hurt it if you prop to achieve Wide Open Throttle rpm of 5500 with only the driver in the boat. Then she'll be just perfect for skiing, watersports, etc. The Merc 1000BP racing motor was rated at 6500 rpm so have no fear of 5500! These old Sixes love to rev.

Then cruise at a lower rpm for best economy, as the O.P. suggested. Best cruising speed vs. fuel economy is typically the max amount of throttle to just get to the distributor stop, where the carb butterflys haven't fully opened. Having propped correctly for max rpm, the loading on the motor will be much less when cruising; you don't want to overprop or "lug" an I-6.

That being said, if that's a stock lower unit it's a 2:1 gearbox and a 100 hp won't carry a 19" pitch prop unless it's on a very light hull. Like 14' or so. A 17" pitch prop will likely get you closer to the recommended rpm range.

Nice clean motor and the power tilt 'n trim is a rare plus!

It'd be a good idea to give the ol' gal a tuneup, a decarbonizing treatment, and replace the impeller if it's been more than a couple of years. Here's some good info from the site on decarbonization:

http://forums.iboats.com/showthread.php?t=158076&highlight=seafoam

HTH & have fun.........ed

 

[MERCNUBEE]

Re: Merc 1000 / advice

i have recently inhereted a classic old baot and motor and am looking for some repair advice. the motor is a 65 or 66 inline 6 merc 1000. don't have picks to share or a s/n but father in law figured it was a 66 - it's covered in silver chrome on the cowl. I ran it once last summer and it ran well but clunked when shifting forward to reverse. eventually I lost the forward shift and had to reverse in to dock.
I've spoken to a mechanic briefly and he suggested probably the shilft shaft is bent or broken. is there a way to trouble shoot without removing the lower unit?

 

[MF67]

Re: Merc 1000 / advice

Thanks fellas!

I will ask him about the bottom half that was switched out.
I think he took it off a 70hp Merc, but is planning on rebuilding the original.

.....