Proper tach setting and RPM?

[emilime75]

What is the proper setting for a tach and a 77 Merc 1150, 115 hp, inline 6 cyl, 2 stoke?

Where should rpm on this motor be at idle and at wot?

Thanks.

 

[Mr. D]

Re: Proper tach setting and RPM?

I have enjoyed the use of a 2 cycle 115 HP inline 6 cylinder Mercury for 15 years without ever having used a tach. My ear was it. Tons of power for a 18 foot Glastron (17 pitch for waterskiing and still 50 MPH). If you know the motor and it sounds good at idle and at WOT, it probably is. That being said, a tach would be nice. If you've got the correct prop on there, have no problems anywhere (powerpack...) and it sounds good, you're probably fine. Do you have a tach? what does it read?

 

[Chris1956]

Re: Proper tach setting and RPM?

The tach manufacturer will have an application table. Normally Mercs of that size use 12P or 6C settings.

Idle speed should be 850RPM or so, Max RPM is at least 5300-6000RPM. Prop her to get at least 5300.