Active Active   Unanswered Unanswered

No (low) power in cylinders 4,5, & 6

Keeping your powerboat under power is a lot easier with good advice. Post your power systems questions here.

Moderators: Don Ayers, Al Benton, Don Vogt

L76
Posts: 23
Joined: Wed Jun 29, 2022 3:09 pm
Contact:

No (low) power in cylinders 4,5, & 6

Post by L76 » Thu Jun 30, 2022 9:29 pm

Hi Guys,

Re my other post on only being able to get to 1500rpm on water… I ran some tests (pull plugs one at a time while engine running) and found that I have little or no power to my back 3 cylinders (4,5, and 6). Thoughts? That second/back carb? I just rebuilt it. KFL motor with 2 zenith carbs. No high speed adjustable keys.

Cheers,
Dennis - L76
1948 Chris-Craft Deluxe Runabout
Spends her time in Tahoe

User avatar
drrot
Posts: 2052
Joined: Mon Nov 14, 2005 12:28 pm
Location: Three Lakes, WI
Contact:

Re: No (low) power in cylinders 4,5, & 6

Post by drrot » Fri Jul 01, 2022 8:22 am

Switch the carbs and see what happens.
Jim Staib
www.finewoodboats.com


1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

L76
Posts: 23
Joined: Wed Jun 29, 2022 3:09 pm
Contact:

Re: No (low) power in cylinders 4,5, & 6

Post by L76 » Sun Jul 03, 2022 12:30 pm

Thx guys.
After some deeper diagnosis… it was the back carb. Found a burr in the air horn that was causing the choke butterfly to stay closed. Modified (filed the burr) and shimmed the choke linkage, replaced some gaskets, and voila!
Engine running strong… but I am witnessing high oil pressure. 70psi while cruising, 30psi while at idle. I’ll post another topic…

Cheers,
L76
1948 Chris-Craft Deluxe Runabout
Spends her time in Tahoe

Post Reply

Who is online

Users browsing this forum: Bing [Bot] and 28 guests