73 Mercury 115hp finding info

[sgmspawn]

Can anyone help me to find info for my 73 merc 115.

like gear ratios and wide open throttle limits etc etc.

Any help would be appreciated .
Thanks

[CrayzKirk]

Hi,

Grab a service manual on eBay...

The lower unit ratio is 2:1 on the 73 and later models. The 70-72 1350/1150s had 1.78:1 ratio. No 1350 in '72 though...

Wide Open Throttle range for an 1150 is around 5500 RPM. They aren't as prone to detonation as the 1500s however keep timing no greater than 21*. Run midgrade gas and good quality oil. Put a water pump in every couple of years, more if you use it year round.

Everything I know, I owe to the board! Thx guys!

Kirk S.

[sgmspawn]

Thanks alot for the info.

Your help is greatly appreciated.

[Raceman]

The 72 1150 was unchanged from 70/71 also and was the only year in Merc history that the two 6 cyl inline engines had different bolt patterns at the bottom of the powerhead and would not interchange.

I'd still recommend Super Unleaded even though as Kirk correctly pointed out, the 1150's aren't as prone to detonation as the 1500's. Remember, these engines were designed and built when the regular gas at the pump was better than anything we get out of the Super Unleaded nozzle these days.