69 Mercury 1000-Reasonable Performance?

[NJCinMN]

I've gotten to know quite a bit about old Mercury inlines in the last month and I've really taken a liking to them. I like the simplicity. Anyway I've been in boats all my life but I'm very new to owning one. So here's the question, does my performance seem reasonable? I'm good in the rpm range of 4800-5300 and getting 35 mph at WOT and get on plane fairly quick.

Info:
-1969 16.5' Glasstron v-163 gross weight 700 lbs (doesn't seem to be water logged but might be a little- it's 40 years old)
-1969 Mercury 1000 (believe boat and motor to be original combo, height and setup seem to be good, anti-cavitation plate slightly above bottom of boat)
-3 blade aluminum prop, 17 pitch
-load: myself and friend averaging about 190 lbs each, 6 gallons of gas, some other misc. stuff but nothing too heavy

-Tuning:
-checked compression and is good
-drained lower unit and put in new lube (dark but no metal or milk)
-new fuel line and primer bulb
-rebuilt both fuel pumps with new check valves
-rebuilt all 3 carbs all new parts (floats, needle, seats, etc.)
-changed all 6 plugs, all have good spark
-did the link and sync and adjusted idle screws

The motor starts right up, idles great, and runs great overall. I just thought it would have a little more pep. At this point I guess it is what it is. I did a decarb but haven't been back to the lake. Maybe that'll be the difference.

Thanks for any thoughts or comments.

 

[emckelvy]

Re: 69 Mercury 1000-Reasonable Performance?

Seems a tad slow, I'd think it'd pull a bit more rpm and hit at least 40. Are you sure your speedometer is accurate?

With a load, what's the precise rpm? 4800 or 5300? It does make a diff what side of the rpm range you're hitting.

For example, if you were hitting 5300 with good hole shot, you could probably "pitch up" to a 19" and get an increase in speed. If you were at the low end, it wouldn't do any good as an increase in pitch would put you out of the motor's powerband and slow top speed considerably.

What does she run with just you in the boat; just a light load? Don't worry about ovverevving the motor, just bring 'er up to Wide Open Throttle for a few seconds until it stablizes. Just don't let 'er go over Six Grand!!!

I had a 16' Sidewinder with a 100 HP on it, performance wasn't exciting, but you could ski with it. If I recall it ran in the low-40's. Now, when I bolted a '71 1350 on the same boat, things got exciting real fast!!!

Last thought, what's the max spark advance set at? These motors are sensitive to timing and if dialed-back too far (not enough advance), you'll lose several hundred rpm. You don't have to set the timing back like you do with the 99 C.I. motors, these have a different piston design that isn't as prone to detonation. Plus having a lower specific power output than the larger motors.

That 100 I had on the Sidewinder slipped timing one day and was running reallly strong. Couldn't figure it out until I noticed the spark advance screw loose and vibrated out. Spark plugs were blue/purple! So I figure it had a ton of spark advance (probably over 40 degrees!) and had no ill effects.

Now, I'm certainly not advocating advancing the timing beyond mfr's specs, but you're not likely to kill the motor either, setting it to those specs. You might want to use mid-grade fuel just for G.P.

Anyway, get a baseline W.O.T. with light load and that'll tell you a lot about what's going on. And if you have a friend with GPS (or someone else to run side-by-side and check speedo calib.) you can confirm your speedo readings.

HTH........ed

 

[NJCinMN]

Re: 69 Mercury 1000-Reasonable Performance?

Ed, Thanks for the comments.

To answer your questions. That speed if off the speedo and tach that look original to the boat (40 years old). God only knows how accurate. I'm gonna borrow a friend's GPS and get an inductive mini tach to put on a plug wire to verify speed and rpms. Max advance is set a 34*. Interesting you say that your adjustment screw came loose because mine did the same thing before I did all the tuning. I was a little worried but it sounds like it not as big of a deal as I thought. No aluminum on the plugs so that's a good sign. But it did run like a bat outta h#ll that day. Also I run mid-grade 89 octane.