Quick question on throttle lever throw-or lack thereof

[Stu Jackson]

"RELATIVE" Tach Readings and PROPORTIONAL Readings

Many folks get "hung up" on "accurate" tach readings.

The first thing to do is to check the dip switches as suggested and avilable in the Tech wiki manuals for Teleflex.

BUT, only if you really care.

F'rinstance, I kinda think of the tach like my fuel gauge (omigosh, what blasphemy!!!).  As many may remember, my fuel ugage is OUT and I use engine hours to measure fuel consumption.

It's all relative for the tach.  Does the engine sound good to you at certain RPM?  Whatever those feelings are is where the "sweet spots" in your engine's performance reside.  It really doesn't matter what the gauge says, it's how it all feels.  On Aquavite, it's 1100, 1500 and anywhere over 2000 where the engine is "purring."  Places in between are somewhat rougher.  It's a three cycle diesel, after all.

It's an analog gauge.  Can we measure 2,653.5?  Do we care?

You can always try this Proportional Method of using your tach ---

To avoid having to take the cockpit panel off to check the dip switches on your tach:

1.  run engine in neutral to full revs (on a "conformed" tach it should be 3,000)

2.  read tach

3.  if tach is less than 3,000, take that full throttle in neutral reading

4.  all other readings are pretty proportional to your max reading to 3,000 (i.e., if you read 2,500 at full throttle, then [2,500 divided by 3,000] times whatever you are reading is your real rpm.

If you don't like this method, then by all means adjust your tach, but know the WOT in neutral should be 3,000 for an M25 or M25XP engine, that is.

[DarthOccam]

Harbor Freight has a laser tach for about $50.00.  I bought one a few years ago and it works great.

Amazon also has a few well reviewed laser tach units for under $15 with free shipping for Prime members.  While you are at it, you can add a infrared thermometer gun (many uses on a boat) and still spend less than $30.

Michael

[Les Luzar]

I'm with Stu,
Fix the throttle lever throw and "Go Sailing." I have too many other things on my to-do-list that I will probably never get to checking my true RPM. Anyway, Never pass up an opportunity on a nice day to go sailing....

[efhughes3]

I agree, and my "feel" is that I'm not getting full revs, hence my original post and my mention on that same thought this morning. Syncing the tach is a secondary operation here.

Saturday is a good cleaning of the boat, the christening, and we sail Sunday!