merc thunderbolt 1000 gas usage

[yonu]

quick question I hope someone can help me out I have a 68 mercury thunderbolt 1000(100hp) I have yet to fit a tank to the boat but since I plan to test start the motor (as I finally got around to rewiring it). So what I need to know is for lack of a better term what kind of gas mileage should I expect from this engine?

Thanks,
yonu

 

[mr 88]

Re: merc thunderbolt 1000 gas usage

Extremly vague. What size boat, how big of a load will you be carrying 2 people -6 people.WOT,slow/fast cruise on plane or trolling,pulling skiers/tubers. What pitch prop in relation to recommended RPMs is also a big bearing on what to expect. So here is a vague answer 1-3 mpg. Most of my day cruises are 20-40 miles so 12-18 gallons is what I carry.You can always take two 6 gallon cans and a 2 gallon spare. When you run the first tank dry the second one will get you home with the 2 as added insurance.

 

[yonu]

Re: merc thunderbolt 1000 gas usage

Hey vague is fine and 1-3 is actually about what I figured.
I have it on a 18ft fiberglass Steury tri-hull bowrider will probably have 3 people on average and no idea on the pitch and no idea on speed as that will depend on activity so let say fast cruise.

Thanks,
yonu

 

[mr 88]

Re: merc thunderbolt 1000 gas usage

I would say about 2 1/2 -3 mpg. Props can be overpitched or under and in both cases it will hurt your fuel consumption. You need a tach,even a temporary one. Then the MFG's rated RPM. So if its rated at 6000 wot RPM and your getting 5000 you are overpitched and working the engine.6500 RPM=underpitched and have to be on the throttle to keep speed up for a fast cruise while your engine is ready to blow from to many R's. This is taking into acct that the engine is running 100% with full compression and fuel delivery.Its better to be a little overpitched then under if you can't hit it spot on.

 

[yonu]

Re: merc thunderbolt 1000 gas usage

thanks I will keep that in mind.

Thanks,
yonu

 

[Gomer50]

Re: merc thunderbolt 1000 gas usage

I agree with the above,with a little humor to add.Dont plan on crossing the ocean because for one a fuel tanker couldnt keep up and second a fuel tanker wouldnt have enough fuel to keep you going.I run a 90hp inline 6 and can burn up about 8-9 gallons in about 2 hours heavy cruising,off and on WOT.

 

[yonu]

Re: merc thunderbolt 1000 gas usage

thanks that really helped guess I will fit a 30 gallon tank after I make sure everything is good on the engine only problem is I will have to take a mortgage to fill it