Thread: Squeezed #3 on the 1390
12-16-2007, 08:28 PM #1
Squeezed #3 on the 1390
I took the ski to Senators Wash this morning. Temp was about 52° water temp about the same. Wind was blowing it was rough. I went out and warmed it up for a good 15 minutes. First by making WOT blasts for about 100 yards, then a little longer then a couple blasts to 75, probably about 1/4 mile. Then rhode around a little more lined it up and pinned it. The water was too rough to superman or really watch the tach like a hawk. I did not notice any drop in RPMs. It was turning 7160. At about the 5/8 mile mark it shut off (speed was 77.1). Now I am really trying to understand if the seizure was due to cold water in the lake or lean condition. There was no soot in the combustion chamber, all wet. Number 1 and 2 look good as far as wash goes.
I switched to 140 main jets from 145's on my last trip. With the 145's it wouldn't make over 7000 rpms at 80° and ran 7160 at 62° the next morning. These are OEM modified to Blackjack 48's. I havent found much info on these carbs on a 1390.
My theory is that I was close to lean due to cold temps with 140's and the cold water wouldn't let the cylinder expand enough. Got to love Wiseco.
Check the picks out and give me your feedback.
It looks and feels like some muriatic acid a mild hone and a new piston and rings and it should be good to go.
I'll go take pics now and post on a response to this thread.
Last edited by spud; 12-16-2007 at 08:35 PM. Reason: clarify reason for 140 main jets
12-16-2007, 08:30 PM #2
Batteries in camera need to charge.
12-16-2007, 08:32 PM #3
12-16-2007, 09:40 PM #4
Spud what was the piston to wall clearance? Reason I ask is that wiseco recommends 40 ths. which is too tight for those pistons if you ask me. I used to run wiseco big bore setup on my xpl. I set my piston clearance to 65 ths. Something to think about.
12-17-2007, 12:19 AM #5
12-17-2007, 12:26 AM #6
12-17-2007, 12:43 AM #7
Maybe a few things combined and not just one thing? Whenever it's #3, and NOT water injestion, I'd be thinking timing and not enough gas...
- Cold water?
- Not fully broken in yet?
- Increased timing?
- Seizeco Pistons?
- Your RAD was 103.15%
- Your corrected altitude was NEGATIVE 1060ft!
12-17-2007, 01:29 AM #8
12-17-2007, 12:26 PM #9
Geez Spud, hope it's something easy to fix. Not fun on a new engine...
12-17-2007, 02:45 PM #10
with your timing advanced are you guys running any kind of race fuel? 140's on blackjacks should be pretty good on that setup I am at 155 on my bb setup.. The only thing with the blackjack carb you should watch close is your fuel pressure should be at 5 1/2 to 6 lbs wide open throttle and 2 lbs at idle
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