Tachometer For Motor Break In

Sevcrist

Seaman Apprentice
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Apr 16, 2005
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If I am breaking in a new Mercury 40hp 4 stroke EFI motor but don't have a tachometer, would this be a problem? Can't I just estimate what the RPM's are at for the break in procedure?<br /><br />Also, what kind of effect would not having a tachometer have on getting the boat propped properly? <br /><br />Basically, what I want to know is am I asking for trouble if I don't have the tachometer for the above situations or any others?
 

Dunaruna

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May 2, 2003
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Re: Tachometer For Motor Break In

In this day and age I'm very surprised that you were sold an EFI 4st without a tacho. If it were me, I'd be going back to the dealer and asking some questions!!<br /><br />No, you can't guesstimate the RPM. The running in procedure is critical. Impossible to properly prop without a tacho. Yes, you're asking for trouble.<br /><br />Aldo
 

Sevcrist

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Re: Tachometer For Motor Break In

The boat is a basic aluminum fishing boat and did not come with a tachometer as standard equipment. I asked the dealer to put one in but they said they looked for 2 weeks and could not find one small enough to fit on the steering console.
 

Sevcrist

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Apr 16, 2005
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Re: Tachometer For Motor Break In

Not any good pictures. This is the only thing that I could come up with. I know it doesn't show the proper view but the MV 1657 SC is the type of console I have.
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Sevcrist

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Re: Tachometer For Motor Break In

Yeah, I see. Or rather I don't see. The boat is a Polarkraft Sportsman MV 1571 SC. If you wanted to you could go to Polarkraft.com and check it out. But again I could not find a good picture.
 

Dunaruna

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Re: Tachometer For Motor Break In

Yeah, I went to the site but couldn't find a pic.<br /><br />What about just right of the driver, next to the control lever. Mount (pop rivet) a 4" square piece of aluminium and mount the guage in that.<br /><br />Do you have other guages in the helm. The smartcraft tacho incorporates voltage, trim, and anything else you may want into one guage - maybe you could swap out other guages for one smartcraft guage?<br /><br />Aldo
 

dajohnson53

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Re: Tachometer For Motor Break In

You could probably rig a Tinytach - you can order them with custom length cables.
 

Sevcrist

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Re: Tachometer For Motor Break In

The console doesn't have any gauges on it but it does have a switch panel. That's what is taking up most of the space, plus the steering wheel.<br /><br />The piece of aluminum is a good idea although it might look out of place. I went to the Tiny Tach site and that looks like a possibility but are their tachs marine rated?
 

dajohnson53

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Re: Tachometer For Motor Break In

Sevcrist - I'm thinking, but I could be wrong, that after you break it in, and determine that the prop is correct, that you might be able to get away without a tach or use it intermittently. Maybe from time to time especially if you think the engine's not acting like it should. However, the Tiny Tachs seem to be well thought of, and they are cheap so if you needed to replace it it would be NBD.<br /><br />That said, if it were my boat, I'd figure out a way to get a tach in there. Without knowing what your console looks like, my guess is that a good fabricating shop could build you one that would look good. Cleanly riveted or welded to whatever surface you think appropriate. Maybe even a small gauge "bank" if you also wanted to put in a trim gauge, pressure gauge, volt meter, etc. All this imho of course, but I've had good luck making stuff like that work given my ideas and the skills of a sheet metal fabricator. You could even prime and paint it if you need to, to make it look OEM. Properly prepped and primed, it's pretty straight forward getting a good finish on aluminum. Many center and dual console set ups on boats around here are custom built by local fabricating and welding shops and they look OEM.
 

pwiseman

Petty Officer 1st Class
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May 4, 2005
Messages
207
Re: Tachometer For Motor Break In

I doubt that you need a tach for breakin procedures. I had the Merc 50 EFI and it does not recommend specific RPMs in the procdure.<br /><br />A tach might help to determine what prop is best, I would think that boat/motor combo would take a 13 pitch, maybe a 12 or 14 depending on how much weight you carry (or don't). Dealer should make a good idea what works and I would trust this advice over mine. If you have a GPS unit, and your speed is in 25-30 range you are close and it should be apparent if you need to go up one or down one. <br /><br />I disagree the comment that indicates you should expect a tach on a boat of this type as a default option.
 

Dunaruna

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Re: Tachometer For Motor Break In

Paul, I respectfully disagree. The merc 50EFI 4stroke manual clearly says "do not exceed 3500RPM for the first hour and then do not exceed 4500 for the second hour".<br /><br />I assume (but don't know for a fact) that the 40HP would be the same.<br /><br />If anyone can determine 3500rpm by ear then that's someone I'd like to meet.<br /><br />Aldo
 

davejnz

Petty Officer 2nd Class
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May 2, 2004
Messages
115
Re: Tachometer For Motor Break In

Those tiny tachs are so small,the mounting options are endless.On my 14'Lowe/tiller i mounted mine directly on the outboard.Best $40 i've spent for that motor.
 

Sevcrist

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Apr 16, 2005
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Re: Tachometer For Motor Break In

I called the dealer and told him that I wanted the tach and that I could wait another couple of weeks to pick up the boat while he was still looking for a suitable tach. I also informed him of Tinytach.com. So, hopefully this will work out.
 

davejnz

Petty Officer 2nd Class
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May 2, 2004
Messages
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Re: Tachometer For Motor Break In

Originally posted by Sevcrist:<br /> The console doesn't have any gauges on it but it does have a switch panel. That's what is taking up most of the space, plus the steering wheel.<br /><br />The piece of aluminum is a good idea although it might look out of place. I went to the Tiny Tach site and that looks like a possibility but are their tachs marine rated?
I use mine exclusively in saltwater and never had any problems.If you decide on one,you'd be better off ordering/installing it yourself to avoid dealer markup/installation fees.Just measure how much wire you'll need from mounting location to motor and let them know when ordering.
 
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