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Re: 1962 Seacraft
Posted: 19 Apr 2017, 19:30
by WoodRay
Re: 1962 Seacraft
Posted: 19 Apr 2017, 21:21
by Greg
Magic!
Re: 1962 Seacraft
Posted: 08 Oct 2017, 19:54
by WoodRay
Ditched the Weber and did a couple of test runs with 2 x HS6 (1 3/4) Su's. Not having much success as they are very lean above 2500rpm and flat spotting. Have had some minor improvement after using double springs! Not sure why I'm having this problem now as I ran twin HIF 1 3/4's with single springs with no problem. Thinking I may have a fuel supply/flow problem.
Re: 1962 Seacraft
Posted: 09 Oct 2017, 18:26
by WoodRay
After a review I realised I was running a Holley red fuel pump with a CR regulator on the HIF's prior to this recent change. I'm thinking too much fuel pressure overcame the potential to lean out up high back then but now I'm not running that pump. I've now gone down to 1 1/2 HS4 Su's, single yellow springs, and am running a Facet 1.5 PSI fuel pump without regulator. Flat spot gone now. Need some water time next week for a good test.
Re: 1962 Seacraft
Posted: 09 Oct 2017, 22:43
by bootlegger
Trial and error. Aooner or later you get there
Re: 1962 Seacraft
Posted: 10 Oct 2017, 15:18
by WoodRay
bootlegger wrote:Trial and error. Aooner or later you get there
Sometimes it's later than sooner!
- Pic_1009_180.jpg (68.57 KiB) Viewed 7582 times
Re: 1962 Seacraft
Posted: 10 Oct 2017, 16:43
by Greg
I reckon, Craig, the problem is with that hammer (bottom right).
It is just not big enough!
Re: 1962 Seacraft
Posted: 10 Oct 2017, 16:58
by WoodRay
Greg wrote:I reckon, Craig, the problem is with that hammer (bottom right).
It is just not big enough!
Haha, the big hammer was out of shot!
Re: 1962 Seacraft
Posted: 21 Oct 2017, 18:12
by WoodRay
Ok made some headway the other day. Managed to dodge the storms and get two runs in at Glenmaggie. In my haste to chop and change before this I realised that I may have not persisted with trying heavier springs in the 1 3/4" HS6's and encountered the same problem. My brain kicked into action by going straight for the 1 1/2 HS4's. Stupid me forgot HS4's run a .090" needle and associated jet so I now I reckon I was getting a manometer effect in the jet when I tromped it. Less fuel reserve capacity in the jet due to smaller diameters were causing the lean out. I fitted the .100" jets and got a massive improvement. Just running out of puff at 3500rpm as the pistons are at full opening due to the light springs. Now ordered some heaviers and hopefully will be right for Narranderra. Maybe some testing/adjusting on the day if I run out of time.
BTW, fuel pressure and flow with the new fuel pump wasn't the issue.
Re: 1962 Seacraft
Posted: 23 Oct 2017, 13:29
by WoodRay
All good today. Ripper morning on Glenmaggie with Ross and "Ratbag"
I pinched the SU springs out of my FB. She launches out the water very well with no flat spot no matter how hard you hit it. Revs nice clean out to a touch over 4000rpm at about 43 mph.
The 1 1/2"s are almost at full opening at full noise. Any cam work or other improvements would need me to go to 1 3/4 SU's.