I've searched using numerous terms, but can't find anything concrete. When sea trialing, the throttle lever hit the pedestal guard, and only allowed about 2500 rpms. We could get 6 knots, at that range. As the new boat is 100 miles away until next week, I can't look, but I'm assuming I could take up some throttle cable on the lever at the engine to get more throw? Anyone else seen this? Thanks,
Welcome. I bought an 88 2 yrs ago and had to adjust the throttle and gear shift cables when I replaced the plastic handles with stainless. The adjustment can be done most easily at the engine, although it can also be done inside the binnacle. There are some references to this on the web somewhere. Assuming there is nothing different about your boat, and that your tach is correct, you should be able to get more than 2500 rpm. I normally cruise at about 2700.
Ed : Your throttle cable definitely need to be adjusted. It should never hit the pedestal guard!
It's a simple matter to take a common tip screw driver at the engine, loosen the screw in the "stop" on the cable, move the throttle at the wheel all the way aft, move the throttle linkage (at the engine) and then re-tighten the cable stop. Then check to make sure (with someone at the wheel and someone at the engine) that you made the proper adjustment.
I would first check the actual engine speed before changing the cable. My tach reads a max of 2500 but that is because I have a 1.25 error in the tach reading. at 2500 my engine speed is actually 2500 x 1.25 or 3125. I do get 7+ knots* however with my 3 blade prop and a m35 engine. The lever did hit the bar before I changed to this folding prop 15" x 10 pitch
* clean bottom and smooth water without exhaust black smoke
Thanks, that adjustment is as I suspected. Numero uno on the to-do list.
Guys : Dale has an M35BC (35hp) rather than a M35 (30hp) engine !!
Quote from: Ron Hill on January 02, 2012, 05:05:59 PM
Guys : Dale has an M35BC (35hp) rather than a M35 (30hp) engine !!
I caught the different engine. I was referring to the adjustment you described.
I have wondered about this too since buying into our C34.
The stainless lever hits the binnacle frame.
As it revved to 2700, I presumed to act as a govenor and no excess strain on the cable.
Since the new bottom job along with new 15 x 10 2 blade prop she hoots along really sinking her stern in.
At full revs, the new Raymarine 60+ speed display indicates just over 6kts but Navionics on iphone suggests over 7
I keep the revs below 2500.
What is the maximum revs she should go to?
cheers
Tony
OK
I was being lazy.
I just googled and found all the info here.
http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-m25xp-specifications.html
cheers
Tony
Tony : I've mentioned this a number of times, but don't take the Teleflex engine tach reading and the "Gospel truth".
What you need to do is use a laser tack and check the engine tach readings against what the engine is actually turning!! Make yourself a chart of a number of points on the engine tach and get the real reading off the laser for that point.
It's only then that you'll really know what the engine is really turning!! A thought
Thanx Ron
2nd opinion always a good idea
cheers
Tony
Harbor Freight has a laser tach for about $50.00. I bought one a few years ago and it works great.
You just have to paint the crankshaft pulley flat black before you put on the reflective tape.
Ed,
I have a 87 with a M25XP and I tend to cruise at 2,700 RPM on my tachometer and my maximum RPM is 3,400. 80% of max rpm is 2,700 RPM. On smooth water this RPM gets me to 6.5 knots, and the engine seems happy at this speed. Just for your reference.
Thanks for the info. I'll get a laser tach and check against the instruments.
I was hitting 6+ kts, so maybe the tach is off a bit. But, it didn't sound close to max RPM.
I forgot how much fun boat ownership was! I'm spending like a drunken sailor now, but it'll be in San Diego this weekend, and I can start to learn every inch of her, and take the wife sailing.
For those that don't have access to a digital tach, here is an alternate.
A florescent light flickers at 60 hz. You can illuminate the crankshaft pulley with the florescent light to do your adjustment. Takes a couple tries to get the hang of it, but once you see it, the rest is easy. I found it easiest to have a helper set the engine at about 1200 on the tach (multiple of 60) then adjust the throttle until I got the bolts heads on the pulley face to "stand still". The throttle adjustment can be done by the person in the cockpit or by adjusting the throttle arm on the engine. Adjust the tach to read 1200 with a small screwdriver through the adjustment hole on the back of the tach. Increase the throttle to 1800, again adjust the throttle to get the bolt heads still, adjust the tach. Repeated at 2400 and 3000. It took me a couple cycles until the tach was close at all throttle settings.
Getting the bolt heads to stand still is kind of like watching an old cowboy movie. Remember how the wheel spokes seem to have a rotation different than the wheels. You will see this on the bolt heads. Simply adjust the speed until the rotation stops.
Don't forget that the tach reads alternator speed, I think by counting the brush segments on the armature. There are switches on the back of most tachs (Called Dip Switches) that need to be adjusted to mate the tach to the alt and allow the tach to read correctly. The first step in tach adjustment should be ensuring the dip switches are positioned correctly. Here are a couple of threads that discuss dip switches.
http://c34.org/bbs/index.php/topic,6492.0.html
http://c34.org/bbs/index.php/topic,1541.msg8496.html#msg8496
"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.
Quote from: Steve Sayian on January 05, 2012, 02:59:25 AM
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
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.... :thumb:
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! :clap