new 60hp yamaha slow

[rodbolt17]

that would be OVER propped.
underpropping can lead to pegging the rev limiter.
most the EFI four stroke rev limit functions are so smooth the operator doesn't know he is on it.
overpropping leads to catastrophic piston failure that most likely may not be covered under warrenty.

underpropping leads to wasted fuel and lack of speed but the holeshot is nice.

[99yam40]

Rodbolt, do you have any info for him on where to hook a tach on that 4 stroke tiller unit

[rodbolt17]

most tiller models of the F motors you have to accesss the ign switch and tap into the green,black and yellow wires.
there is a harness for that.
I typically use my stevens timing lamp on tiller models with no tach during the PDI test run.

[Bass Cat]

I borrowed a tach from a friend. It is called a Tiny Tach, you hook it to a plug wire and it is supposed to read true. Any thoughts? I appreciate any help.

[TownsendsFJR1300]

I borrowed a tach from a friend. It is called a Tiny Tach, you hook it to a plug wire and it is supposed to read true. Any thoughts? I appreciate any help.

It should (maybe not) have some settings for 4 stroke, 2 stroke, etc. Just make sure its set correctly.

If you have another machine you can test it on wouldn't hurt..

You can test it on your 4 stroke lawn mower engine. WOT on the mower will likely be between 3,000 and 3,600 RPM's.



The Echo one I posted above showed 3,000 RPM's WOT on my Snapper mower(factory setting-wated spark). Max torque-3,000 RPMs, max HP-3,600. B&S recommended 3400 RPM's, +/- 100. I bumped up the governor to 3440, cuts/muches SO MUCH BETTER..

[rodbolt17]

just remember most F motors in the small to mid range use waste spark ign.
when using an inductive tach on waste spark four stroke you may have to divide by two .

[Bass Cat]

Thanks for the help, you guys are a wealth of information.

[Bass Cat]

Just hooked the tach up with a set of ears and at idle it is turning 1500 rpm's so I will have to divide by 2. Going to take it to the lake today to see what W.O.T. is.

[boscoe99]

Rodbolt, do you have any info for him on where to hook a tach on that 4 stroke tiller unit

Might be a bit late for this guy but the connection points for a Yamaha tachometer are within the tiller handle itself. A plate on the bottom of the tiller handle can be removed for access. Then it is just a matter of plug and play.

[Bass Cat]

More confused now. I went to the lake, the tach read 1500 at idle, a little over half throttle it was reading 8900, while I was going to full throttle the tach went to 5000 and at full throttle it read 6100 and I still had a little trim left so I backed out of it and put it back on the trailer.

[TownsendsFJR1300]

More confused now. I went to the lake, the tach read 1500 at idle, a little over half throttle it was reading 8900, while I was going to full throttle the tach went to 5000 and at full throttle it read 6100 and I still had a little trim left so I backed out of it and put it back on the trailer.

Sounds like the tach was acting up or it picked up a signal from TWO plugs at the same time momentarily.

[Bass Cat]

it would do it every time you got over half throttle and when you would back off to half throttle it would read double

[TownsendsFJR1300]

Is it a portable tach or how is it hooked up?

[Bass Cat]

It just clamps to a plug wire and to ground, probably will have to buy a good one just hated to for one time use but I do want to make sure the motor is right.