speed for a 9.8 hp

[ljcatman]

what's the fastest speed a 1972 mercury 9.8 hp motor will go and the slowest speed just want to know. and one more question how long will a 6 gallon tank of gas last on a lake 1/2 a day or all day

 

[d.boat]

Re: speed for a 9.8 hp

what's the fastest speed a 1972 mercury 9.8 hp motor will go and the slowest speed just want to know. and one more question how long will a 6 gallon tank of gas last on a lake 1/2 a day or all day

First questions can't be answered at all because it totally depends on the boat. When I was young, we had a Merc 9.8 on a little homemade plywood hydoplane racing type boat. That thing really moved, I'll bet 20 mph. My current, very similar 9.8 pushes my 20' boat at about 5mph.

Second question: fuel usage depends totally on what you're doing. If you're running the think full bore, it will burn 1-2 gallons per hour. If you're trolling, it will burn a tiny fraction of that.

The only thing you can do is carry a spare gas can of pre-mixed fuel with you for the first few times you use the boat and make an effort to figure out what it is burning for you.

 

[kenmyfam]

Re: speed for a 9.8 hp

what's the fastest speed a 1972 mercury 9.8 hp motor will go and the slowest speed just want to know. and one more question how long will a 6 gallon tank of gas last on a lake 1/2 a day or all day

You just asked "how long is a piece of string"
What is the entire outfit the motor is going on ??? with what load in it ???
The more info the better the answer.
As a start, the slowest is zero mph, that is when you are tied to the dock with the motor off.

 

[steelespike]

Re: speed for a 9.8 hp

I would say with a perfect stock set up on a light fast boat about 20-21 mph.
with the idle lowered a very slow trolling speed.
Rule of thumb wot(wide open throttle) about 1 gallon per hour.
my guess is trolling speed about 1/10 of that.