Pontoon Boat & Deck Boat Forum

Well, the pontoon is running much better, but I don't think I'm getting the HP out of it that I was last year. I've got a couple of questions.

First let me state that I know that I have some water in one of my toons, just not sure how much yet. I hope to get rid of that problem this week, so this could be a cause of some of my HP loss.

Yesterday I was pushing almost 7000 RPMs at full throttle, but it didn't seem that taxed out. Is there a way that I can check to see if my Tach is working correctly? If it is working correctly what would cause it to run that high?

Last question, when I shut off the motor I can hear the prop spinning to a stop (click, click, click, click), is that normal? I don't actually remember that sound last year either, it may have been there I just wasn't hearing it.

thanks in advance for your input.

If your tac shows your running 7000 rpm it is bad or your over revving.

lakerunner696 wrote:If your tac shows your running 7000 rpm it is bad or your over revving.

LR,
ur saying the tach may be bad....or are u saying that it's just bad for me

I think he is saying the tach may be faulty. If it isn't a faulty tach then you may have a prop dimension issue, ie... too small in diameter or pitch. Do you know what you engine's max RPM is supposed to be. I am sure 7000 RPM's is too high. If that is an accurate reading you are passing the redline of you motor which isn't kosher.

You might have a bad tach. I over rev'd mine when I started it last week, and the tach no longer works.

If you don't throw your engine into neutral before you turn off the ignition, and you have forward motion--you'll get a click, click, click. That's normal.

Ron Burgundy wrote:I think he is saying the tach may be faulty. If it isn't a faulty tach then you may have a prop dimension issue, ie... too small in diameter or pitch. Do you know what you engine's max RPM is supposed to be. I am sure 7000 RPM's is too high. If that is an accurate reading you are passing the redline of you motor which isn't kosher.

According to the manual the max RPM range is 5000-5500. How can I tell exactly what my diameter and pitch should be?
I know on the back of the motor just below the drive shaft housing there is a small sticker with a 13 on it, I took that to be the recommended diameter, would that be correct?

Sorry for the scare. If your motor hits 7000 RPM your way over limit. Your rev limiter should kick in so I suspect your tac is bad or not set right.
Again sorry for being clear

jeffybear wrote:

Ron Burgundy wrote:I think he is saying the tach may be faulty. If it isn't a faulty tach then you may have a prop dimension issue, ie... too small in diameter or pitch. Do you know what you engine's max RPM is supposed to be. I am sure 7000 RPM's is too high. If that is an accurate reading you are passing the redline of you motor which isn't kosher.

According to the manual the max RPM range is 5000-5500. How can I tell exactly what my diameter and pitch should be?
I know on the back of the motor just below the drive shaft housing there is a small sticker with a 13 on it, I took that to be the recommended diameter, would that be correct?

The prop dimensions should be stamped on the prop itself somewhere. Finding the exact dimesions for your application is a little trickey. First, you need to address your tach issue because you need an accurate reading before you can adjust your prop size. It is possible that your prop is the right size, and the tach is just giving you false readings. What RPM's are you idling at? I'm not sure how to diagnose a tach problem, but I am sure somone else can give you advice.

This may sound too simple but it works for me. Next time your out after starting the motor see what your tach is reading. If the idle RPM is high also like above 1500 then tap on the tach face with your finger and see if it settles down to 5 to 700RPM's. I've had this happen to me several times, I think it caused by static electricity. Last time it happened several weeks ago I was indicating 4000 RPM at half throttle, tapped on the glass and it dropped to 2500 which is correct.

I'll try the tapping solution today. If this doesn't work is there anything special that I need to look for in a new Tach, will most just swap out with the one I have? New territory for me here. I did check the back of the tach last night and noticed that it was either set on 6c or 6b, couldn't tell exactly which it was pointing to, but these were opposite of each other so I know it was one or the other.

I read on a Merc forum to note what setting your tach is set on the back and with a small screwdriver spin it around a couple times on the adjustment. It think it just cleans the contacts. Fixed my issue for a couple of years so far. Just another thing that doesn't cost anything to try

My tach was doubling the RPM for a while but after I cleaned up all the wiring behind the dash it straightened out. I think it may have just been a bad connection in the bullet connector from the controller.

As for your prop thing. If the boat is still moving and you shut the motor off in gear, it will "click click" until you stop moving. That is normal.
Fishermen will tell you, you should always shift to neutral before you shut the motor off. That click thing scares the fish. If it does it in neutral, adjust your shift cable. It isn't coming all the way out of gear (or you have water in the foot instead of oil ... a bummer)

chill'nthemost wrote:I read on a Merc forum to note what setting your tach is set on the back and with a small screwdriver spin it around a couple times on the adjustment. It think it just cleans the contacts. Fixed my issue for a couple of years so far. Just another thing that doesn't cost anything to try

Chillin'
Thanks for this info, not totally sure this is what did it, but I did as you suggested and I did not have the problem at all yesterday. She ran like a top and I was just barely over 5k RPM with her maxed out. I'm giving you all the credit. I didn't even have to tap on tach.

That's great! Thanks for letting me know it worked for you.