Running In.....

[Spike]

Just got my boat 'Ribcraft 4.8 with 60 yamaha', just wondering what sort of performance i should be expecting from this set up? Ribcraft said approx 35knots+, however having now run 5hrs on the engine a quick blast seems to be around 30-31 knots engine trimed out 3 . Is this likely to be due to a tight engine? i did have 85ltrs of fuel onboard though....Has anyone got any thoughts on this or any expirence with this set up....
Cheers Mike

[Biggles]

No thoughts on your exact boat. But experience tells me you probably won't have the best prop. Check your manual and if you have the standard prop don't be afraid to do some experimenting.

Once its run in log some details such as max RPM (WOT) and speed then list them on RIBNET and we can take it from there.

[Spike]

Originally Posted by Biggles

No thoughts on your exact boat. But experience tells me you probably won't have the best prop. Check your manual and if you have the standard prop don't be afraid to do some experimenting.

Once its run in log some details such as max RPM (WOT) and speed then list them on RIBNET and we can take it from there.

Hi Biggles,
Cheers i should finish running in before the end of the week, it is running a standard alloy 11 1/8 X 13-G at the mo & pulling 5200 to 5300rpm WOT....but still not up to the 10 hrs yet. Yamaha recomend 1hr @ 2000rpm then 1hr @ 3000rpm then WOT for no more than 5 mins at a time (vary the revs).
Mike.

[matt h]

on my 4.8 i had, i ran a 70 fs Suzuki and WOT got 35 but it used to chine walk at 33-35 badly at the latter figure,, loved the boat tho!!

[Bilge Rat]

Originally Posted by Spike

Just got my boat 'Ribcraft 4.8 with 60 yamaha', just wondering what sort of performance i should be expecting from this set up? Ribcraft said approx 35knots+, however having now run 5hrs on the engine a quick blast seems to be around 30-31 knots engine trimed out 3 . Is this likely to be due to a tight engine? i did have 85ltrs of fuel onboard though....Has anyone got any thoughts on this or any expirence with this set up....
Cheers Mike

Hi Mike - i put the same engine on my 4.7 Avon, ran in for 10 hours with the same size prop you have on yours, and could get 35 - 36 knots on a flat calm day, though the Avon is a lot lighter than the 4.8 Ribcraft, i never tried changing props as i wasn't that bothered about going faster, and everything worked well. The Yam in my opinion is a very nice engine, i never had a squeek out of mine in over a year and it still ran like a dream even after being turned over.

[jyasaki]

Is that Yam 60 a 4-stroke?

The Yam specs say WOT for that motor should be 5000-6000 rpm. Ideally, you want to be near the upper end of that range with a normal load.

I wouldn't mess with it until you can run the thing for quite a bit WOT (i.e. wait until after break-in.) Do your prop testing then.

jky

[Spike]

Originally Posted by jyasaki

Is that Yam 60 a 4-stroke?

The Yam specs say WOT for that motor should be 5000-6000 rpm. Ideally, you want to be near the upper end of that range with a normal load.

I wouldn't mess with it until you can run the thing for quite a bit WOT (i.e. wait until after break-in.) Do your prop testing then.

jky

Hi Jyaski,
Yes i think i will leave it until im up to approx 15hrs then a Ribcraft techi is coming down to do a prop test on the boat to see what stainless prop i can fit & if i can go bigger or even if i need to. I would like a bit more on the top end ie:34>35 knots, just so that i can get a cruising speed of about 28>30 knots for flat weather conditions but we will see.
Cheers all Mike.