Blaster1200 question. underpropped or running lean on the top?

[vdubspeed]

So I installed a beat ass old GP1200 motor with good compression into a WB1. Today I took it for it's first lake test and it did good but has a LOT to offer!

First off...my stock 98gp1200 pulls like a train from idle to WOT.

The blaster is setup as follows:
- 100 lows
- 135 highs
- 1.2 N/S set at 63 psi pop off
- 1.5 low out
- 3.0 high out(needed lots of fuel..more on that)-
- 120ish compression across the board
- Ocean pro flame arrestors
- Solas 14/21 as recommended by Impros

So I can't just grab WOT. It will bog. If I easy out of the hole...it will accept 75% throttle.

Anymore than that and it looses speed and sounds like it's hitting a limiter. When I started on the lake today with 1.0 out on the highs...plugs were WHITE. Pulling the highs out got me a nice tan color but I'm still wondering about the WOT.

My question is...should I get a little more prop or go up on the mains?

Thanks

Jason

[quadzilla]

My question is...should I get a little more prop or go up on the mains?

Thanks

Jason

Hey there Jason...

I would very much doubt you need to go up on the mains..

If anything you need to go up on the prop a LOT.!!

On the 144mm pump you will likely need to be around a 16~23 pitch..

If you are still on the 144 pump you will be HARD into the limiter almost immediately..

Have any mods been done to the motor.?

[vdubspeed]

Yes sir...still on the 144. Seems to work for most people. the 155 is too much work and I just put a Blowsion metal 144 pump shoe in and won't be doing that again anytime soon! LOL.

I was thinking the SAME thing. I was thinking 15/22 but might just make the jump to 16/23.

The motor is BONE stock. Unknown history. Tested the compression again tonight at 121-122 across all three cylinders. Starts AWESOME hot or cold. Pulls like a freight train from 5-75% It's seriously a riot. Can spin around, sink down and then launch itself out of the water. Water skips real good to. John Boat wakes are enough to get her to launch!!! I absolutely love the build...just want to be able to grab the throttle instead of feathering it.

When impros suggested 14/21 I was a little leary but went with anyway. Kept reading and then really felt like I was under propped. After riding today...I'm certain I'm feeling the rev limiter.

[butterbean_29512]

Saw a WB2 locally for 3500. Has a 1200 and the 155mm pump. It's sharp looking.

[vdubspeed]

Just wanted to follow up. I found my problem and I almost hate to admit it. Reading the plug wasn't working...because I had the wrong plugs. I had 3/4 inch length instead of 1/2 length which cause the lean indication. She now has the correct plugs and I'm leaning her out slowly.

Lesson learned!

[quadzilla]

Just wanted to follow up. I found my problem and I almost hate to admit it. Reading the plug wasn't working...because I had the wrong plugs. I had 3/4 inch length instead of 1/2 length which cause the lean indication. She now has the correct plugs and I'm leaning her out slowly.

Lesson learned!

Well done on finding this issue..
- you could have had yourself chasing a ghost with the wrong plugs installed.

I still reckon you'll need more prop and less jet going forward..