new 60hp yamaha slow

[Bass Cat]

I have a 1752 allweld aluminum boat, had a 40hp 4 stroke and just bought a new 60hp 4 stroke. The 60hp is no faster than the 40hp was. The 60 hp does not gain any speed after half throtle. Any help would be appreciated.

[DennisG01]

Double post. See this thread: http://www.yamahaoutboardparts.com/f...html#post99029

[robert graham]

If you had a tachometer you could check your engine RPM's at wide open throttle....should be in the 5500 to 6000 RPM range if your engine is running right And if your prop is correct for your boat/motor set-up....you may have to change props to get the speed/RPM's correct....

[Bass Cat]

The only thing I see on the prop is 13 G

[rodbolt17]

G is the series, all G series props are interchangeable as far as fitting the shaft.
13 indicates the pitch.
there are about 4 diameters of the 13 pitch G series prop.

[boscoe99]

Proper propping prevents poor performance. And can prevent engine damage.

That motor needs to be propped so that when the boat is loaded it can turn at or near its redline (6000 RPM) with the throttle wide open and the engine trimmed up only to the point of maximum efficiency.

It is easy enough to double check that the throttle valve is wide open when the throttle handle is fully advanced. If so, I would suspect that the motor is over propped. Meaning it has too much pitch and/or too much diameter for that motor on that boat.

Do you have a tachometer installed? If so, what is the WOT RPM for the conditions noted above?

[Bass Cat]

I don't have a tach on it, how hard is it to install?

[robert graham]

I believe there's an item called a Tiny Tach which is sort of a temporary tach that folks use to motor tuning and troubleshooting....maybe research it and borrow one?...It would really help you focus on your boat/motor/prop performance....

[Marc Kruse]

This might help a little, but without a tach it's just a guessing ****.

http://yamahaoutboards.com/sites/def...sa6d84.tmp.pdf

[Bass Cat]

The dealer gave me a 11x15 prop to try. Going to try it todayand see if it runs any better. Still going to hook a tach up to be sure. Thanks for the help, will repost when I hook the tach up and have more info.

[rodbolt17]

STOP
back away slowly.
find a real dealership.
11x15 is going to make things quite possibly worse.
FIRST install a tach.
then find out is the motor lugging,overpropped, OR hitting the rev limiter, underpropped.
UNTIL the tach is installed ALL further running/testing is not only STUPID it can lead to non warrenty covered catastrophic engine failure.

goes back to that PDI sheet that some dealership gundecked(lied about).

[TownsendsFJR1300]

For a portable tach that can be used on various engines, I did a bunch of research and ended up buying this one;

Echo ENG TACHOMETER [99051130017] for Echo Lawn Equipment | eReplacement Parts

http://www.youtube.com/watch?v=3ozUrUZ25LE


Extremly accurate (within 10 RPMs). This site was the cheapest I could find (it goes upwards of $175). Just something to consider.

[Bass Cat]

Does anyone know how hard it is to hook up a tach on a tiller handle motor? I think the Yamaha dealer does not know what the hell they are talking about. The prop they put on the motor when I bought it was a 10 3/8x13 and the boat with a GPS ran 35 mph then they said it needed an 11x15 and it ran 34 mph but with my 40 hp on the same boat it ran 36mph. They told me yesterday that was probably all the speed I would get out of it because it is an aluminum semi v hull.

[TownsendsFJR1300]

When I re-powered, the shop way under propped the the engine, would barely hit 5k. The engine was such a dog...Once re-propped to 5800-5900, a whole different machine...

They had the trim tab in the wrong direction (its in big letters in the owners manual the direction) as well, it really liked to do donuts. Spent a day re-wiring the rats nest under the console.

Doesn't surprise me...

[99yam40]

have you thought about looking at or asking for the PDI sheet Rod has been talking about, and has your motor been set up in the Yamaha warranty system yet if they did not do the sheet?
Did they even run your boat with this motor on it to fill out the PDI properly?

Look at this web site to find a rig like yours to see what performance they got and what prop they used
Performance Bulletins | Yamaha Outboards


Rod or boscoe will have to comment on the hook up of tach on a 4 stroke, but you need to tell them what tach you are going to hook up