RPM needle buried at half to three-quarter throttle

PensacolaJason

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I am having an issue with my boats RPM gauge needle being buried at 7,000 RPMs when only at half to about three-quarters throttle. I have a Evinrude 130 E130TLEDM and I believe it should top out at 5500 to 6000 at full throttle, so I’m not sure why mine is hitting 7000 RPMs at just half. To be clear, the motor sounds okay to me and doesn’t seem to have any issues that I can tell, but the RPM gauge has me worried.

Im not sure what to be looking for when this happens and whether it could just be a faulty RPM gauge or something with the motor. I am including two photos of the gauge. One is my motor at idle and the other shows the gauge needle buried at 7000. Any help would be appreciated.
 

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F_R

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Is the gauge a match for the motor (alternator tach)? Does it have a setting on the back to select the number of pulses per revolution?
 

poconojoe

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Was it always like that? Is this setup new to you? Automotive tachometers sometimes have a switch in the back for 4, 6, or 8 cylinder engines. Maybe check for that.
 

racerone

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These tachometer usually run off the alternator ( stator ) and yes there is a setting for the number of pulses.-----Nothing to do with the number of cylinders.
 

Joe Reeves

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1996 130hp Evinrude..... Your picture of the idle rpm indicates it's idling at 1200 rpm. That's fine if your engine has a 25" shaft and you're running on a flushette... otherwise either the engine is idling too fast or the tachometer is set wrong.

Set it on #6 (6 pulse alternator setting) if there's an adjustable dial on the back of that gauge... then get back to us with the results.
 

PensacolaJason

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It’s a new tach that was installed by a marine mechanic when this boat had a 115hp Johnson on it. The tach never worked until I put this newer motor on the boat and re-booked up the wiring, so this is new to me. I believe I did see a dial on the back. I will check this afternoon and report back.
 

PensacolaJason

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1996 130hp Evinrude..... Your picture of the idle rpm indicates it's idling at 1200 rpm. That's fine if your engine has a 25" shaft and you're running on a flushette... otherwise either the engine is idling too fast or the tachometer is set wrong.

Set it on #6 (6 pulse alternator setting) if there's an adjustable dial on the back of that gauge... then get back to us with the results.

So even though it’s a V4, I should try setting it to 6P?
 

PensacolaJason

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Okay, will do, was just trying to get as much info about it so I can learn something about them. Mine was set to 4P. I changed it to 6P and will test this week and update this post with my results.

I assume that would cause it to read a higher RPM for both idle and when giving it throttle.
 

GA_Boater

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Set on 4P vs 6P will cause the tach to read higher than it should. Why? Because every revolution of the motor makes 6 pulses when the tach is expecting to count 4 pulses per rev.
 

PensacolaJason

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I was able to run it on some muffs after changing the setting and this is what I’m getting now for idle, which is more in line with what I should be seeing I believe. I’m going to try and run it in the water this week. I’ll make sure to post results from that test as well.
 

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Joe Reeves

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I was able to run it on some muffs after changing the setting and this is what I’m getting now for idle, which is more in line with what I should be seeing I believe. I’m going to try and run it in the water this week. I’ll make sure to post results from that test as well.

The model number indicates your engine as having a 20" shaft so your latest reading at idle on a flushette at 1100 rpm is pretty close to where it belongs (1000). If all is well, I'd leave it where it is. Let us know the outcome.
 

PensacolaJason

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Dropped the boat in the water and ran it. It's now reading the proper RPMs at idle and when giving it throttle. So it was just that dial on the gauge that was the issue. Thanks for the help.
 

Joe Reeves

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So even though it’s a V4, I should try setting it to 6P?

I see via post #13 that all is well now with your rig... good for you.

I just wanted to clear up your confusion between the V4 & the V6 here.... The 3 cylinder, V4, V6 and the V8 all have the same six (6) pulse charging system. Some of the smaller hp models vary. The setting of #6 has nothing to do with the number of cylinders. It is the "pulse" setting that you are dialing in.
 
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