5m glass. Whats cheaper 70hp or 130?

[WalrusLike]

As I look around for a 5m 'ish glass boat, with newish motor, for hardly any dollars, I wonder what size motor would be cheaper to run.

Sometimes they seem to have 130hp on em sometimes 65-70. Mostly on the used boats in my price range, the bigger ones seem to be older motors, and the smaller ones are often newer.

As I am about to cripple myself financially buying a boat that I cant really afford, the running cost is going to affect how much I can use it.

Anyone know in ballpark figures whether a 4.7-5.2m glass boat will be cheaper to cruise with a old 130hp or say a '96 or later model 70hp? (all 2 stroke...) Any thoughts appreciated.

[Noelm]

maybe the older ones with the bigger motors are still going because the motor was suited to the boat, but the smaller ones were flogged to death and needed to be replaced? what you are asking is almost imposible to answer with any accuracy, no idea how the boat is to be run, how heavy any of the boats are, but a 70HP will use a lot less fuel, and be cheaper to service than a 130HP if they are run the same way. Not too sure if that is any sort of answer, but thats all I've got.

[cormorant]

don't let a boat cripple you financially. Better off to wait than to buy one that is not rght now that you will spend heaps on repairing etc.

Just trying to say that it is better to get the right boat at a good price rather than go teh bargain as you couldn't afford the one in good nick.

As formotors the smaller motor may be enough but heavily loaded it will struggle and will never attain teh same top speed ( you don't use that much anyway) . The main thing is to make sure it isn't underpowered as that will decrease teh motors life and make it a disappointing ide.

Many dealer packages are sold with the bare minimum as it is cheaper to package up and also a cheap trailer. 10 years down teh track these can really struggle as they have been run overloaded much of their life. A lt depends on how much stuff and people you load into them and if you also want to do wakeboarding, tubing or skiing.

As for fuel - probably your smallest cost unless travelling big distances to fishing groundsand it all depends on how fast you want to go and how loaded up your motor is. Look for fuel consumption numbers of people with similat weight boats in teh boat tests for a estimate.

Don't stretch yourself too far. Between overtime to pay for it and teh depression of fearing to take it out and leaving it in teh front yard i will send you nuts.

Buy something smaller and more affordable an duse it moor often and use a mate or rent a boat for teh bigger trips

[WalrusLike]

Thanks guys for your helpful thoughts. I know its a impossible ask...

I hadnt thought about the underpowered motor lifetime thing.... good thought. And yeah your right it is probably the smallest cost... but it must be paid for each trip so when dough is a tight it will come into mind.

If anyone has taken a smaller motor off and upgraded to a bigger.... did it end up costing more in fuel for same trip? (Although probably done faster)

If you got there faster thats less time sucking from the fuel tank. Must be someone who has done this. Although it will no doubt be complicated by increasing tech improving efficiency.

As for the cost... yeah its a bit dumb... but we wont loose the house or anything.. just means no fat in the budget for a while afterward. I hate debt... but the kids are getting older.. need to give em some good memories while still at home. Oh... and I really want a boat!!! :)

[Skusto]

had a 115 4 stroke yamaha upgraded to a 150 etec fuel would be pretty much identical. put it this way went out a few weeks ago to hutchies for a bit of trolling and some drifting form scarbrough for 65l of fuel for 6 hours running the old yamaha 115 would of been pretty much the same.. so yes more power can mean pretty much same economy.

[cormorant]

Motors have a sweet spot where they run on a hull at the best KM per L. It is different for every combination. Props play a huge part in the equation. Look at boat tests

A hull in displacement mode - ie trolling at 6 knots may need 30 hp to do so . In a big motor that may be at 1200 revs and in a smaller motor 2000 revs.

The large rmotor my have the boat planing at 3000rpm but the smaller at 3500rpm.

The newer the motor the less fuel it will use.

Comparing a 1980 carby 2 stroke a current model 2 stroke will use 75-80 % of the fuel


A new technology injected 2 stroke or injected 4 stroke will use about half a original carby 2 stroke.

A carby 4 stroke is somewhere between.

Too many variables to give any sort of answer.


Just make sure the motor has a good service history and check it out properly including batteries prop and all controls . Trailers can also be money pits so check it out as well.

Don't rush it and negotiate hard as there seems a lot of boats about and eventually you will find a honest boat with a honest seller and that is possibly more important than the HP size as long as it isn't really underpowered..

[Wayne_Red]

Once you go over 4.7 a 70 would start to stuggle with power @ 5.2 would be better suited with a 90 or 115 and yes fuel $ go up.
As a example I have a 4.5 haines with a 70 yam and on a round trip to spot x of @50km I use @26-27 litres every time. A mate has a 5.2 glass boat with a 115 yam and he does the same trip but uses @35 litres. both open runabouts.
But if I had my motor on his boat it would really struggle for power.
Most 2s motors from the mid 80's through to late 90's where your looking, even up to now are more or less the same engines with very little change, design and economy wise. An old 75' model 3 cyl 70 jono would probably use the same 26-27L as my later model 3cyl 70 yam does
Regards Wayne

[Daisy Burnett]

Along wiht the fuel consumption there is allways the strain on an under powered boat. Better an easy running motor than one that is straining all the time. You will save heaps on maintenance and replacement.

Daisy