90hp,1140cc(69.5ci)yamy pro's and cons

[Fast Fred]

[yamonster]

Do you have pics of the hull? I am building one also (90) currently it is on my 14' Alli.

[Boatnut]

Hey yamonster,
I only have a couple of progress pics at this stage. boat is covered in dust and motor bits hangin all round the shed
The boat is now pretty much back together and i've got just a few more things to do before testing. I hope to run it in the tank on Sat. If all goes well i'll drop it in the lake Sunday.
I'll get get some more pics now she's lookin' purdy and post em up next week.
is it a wingboat your building?, i ain't seen any others around sure would like to.
I'd be real interested in seein' what your up to. Got pics?
What motor mods have you done and how is it workin' out for ya?
what props ya runnin? A bloke racin in Sydney a couple o weeks back was runnin' a 90 yam 20" mid on a 11' boat He was spinnin a full size 24p quicksilver exhaust over chopper, said he was pullin 6500 had nose cone without low pick ups and was runnin way high, lookin for an engine rebuild i thought.

[yamonster]

Nut I am building a motor, For now I am running an Allison, When the motor is done I will hang it on a SST60 hull. For now I have the motor from my fishing boat on the alli. I did a fresh rebuild balanced the pistons, raised the exhast .080 And shaved the head to get 145 psi. raised jets one size. No LWP 26p hubbed cleaver 5800rpms GPS's @ 67.5 for now. The new motor I am building F Fred will build me a tuner and hopefully an exhast plate, Jay smith will be lightening rods and pistons, Berg will be porting a block for me. This is all happening real soon, I am working 6 - 7 days a week for now and will be wed in a month, so my project has to wait for a little while.

[yamonster]

REPORT Boatnut, We need a progress report

[Techteam]

Yam 90 is a good engine for tuning. I ran 76mph with a 26 yam prop and still have a cut down 28 quicksilver which was good as well.I just ordered the Bobs Machine shop nosecone for a merc v6 and filled the water intakes then used a stainless steel banjo fitting into the water pump. I recommend you tack the nosecone on with the welder but be careful not to get the case too hot just a few small tacks, if you just use the epoxy it is forever cracking. I used plastic padding chemical metal for all the fairing and it worked really nice with no cracks at all for 2 years or so.

[Boatnut]

Progress is good. Ran it a couple o weeks back but when checking bolts and stuff afterwards i got a bit spooked by what i thought was slightly excessive movement in tha big ends. I figured a freshen up would be cheaper than boring/sleeving/pistons rods crank,ya get the picture. Got it done last weekend and started running in the new rings yesterday.
Seems i'm way under propped but, 1st day out was spinnin a 14 x 22p exh over chopper ta 6800. i will be playin around with the setup this weekend but i reckon i'm gunna be huntin for sumthin with more legs.
Just coming into tha good weather here so i'll be spendin tha season workin on tha setup, this hull has only had a 2cylinder on it in it's past life so i got a lot to try for the summer.
This is the only pic I have got of it on the water so far, got a test n tune day on Sat and i will try and remember to get more better pics

[Boatnut]

yeah techteam, bobs cone with low p/u's is next on tha list but if anyone out there has anything in st/st 14"dia 24-26 or even would try 28p that they would be willing to part with PLEASE let me know
been keeping an eye on ebay but 24's seem to be as rare as rockin horse sh!t and the few i have seen are pretty pricey. Got ta watch the dollars, the minister of finance and war is lookin over my shoulder.
Also Yamonster congrats on tha wedding best of luck, my advice, hangon to tha toys ya got

[yamonster]

Boat, got the pics. Nice, keep in touch.

Team, what RPM with the 26?

I am running a 26 merc, 5900rpm. 70.5mph so far, motor is barely touched