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View Full Version : Basic maintenance on a older 350


jodynich
08-01-2005, 01:52 PM
We have a Minx that has been tuned up every summer but I don't think its ever been really just given a good run through. I took it out this weekend on the Smith Lake poker run and GPS'ed it at 55.0 with the tabs all the way up and pretty decent water. I think I was turning a little over 4,100 RPM's too. Is this a good speed for the boat or is it being held back? I've heard some Sea Foam would be good for it. What else would yall recommend doing to get a few more MPH out of her?
gcarter
08-01-2005, 03:49 PM
It depends a lot on what prop you're running. How many hours are on it? It may be getting tired. All of these boats are 17-19 years old.
Have you seen this Minx hull # list I've been working on?
http://www.donzi.net/forums/showthread.php?t=39260
If you don't see your boat listed here, please send a PM with the pertinant data, and I'll include it.
Good luck. :yes:
jodynich
08-01-2005, 04:12 PM
We are #68. I really don't know what prop I am running, how do I find out?
MOP
08-01-2005, 04:33 PM
We have a Minx that has been tuned up every summer but I don't think its ever been really just given a good run through. I took it out this weekend on the Smith Lake poker run and GPS'ed it at 55.0 with the tabs all the way up and pretty decent water. I think I was turning a little over 4,100 RPM's too. Is this a good speed for the boat or is it being held back? I've heard some Sea Foam would be good for it. What else would yall recommend doing to get a few more MPH out of her?

It may be over propped but before you start fooling with that you need to get an idea of what shape the motor is in. The best is a compression test, I would hope for 120lbs being your lowest reading figuring the age of your engine. When it was new it was up around 150-160, there should be a max variance of 25% between the upper and lower readings. If that turns out well then go for a good tune up and a lower pitched prop, I am guessing that it is a 260 Mercruiser a hunch would be 19- 21 pitch. I would shot for 4600 maybe a tad more, 4100 is to low makes everything work harder.

Phil
gcarter
08-01-2005, 05:39 PM
We are #68. I really don't know what prop I am running, how do I find out?
If it's a Mercury prop, there will be a number on the side of the hub. Usually the pitch is the last digits.
On other props, sometimes the number is on the end of the hub, near the center.