Active Active   Unanswered Unanswered

KL idle

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

Moderators: Al Benton, Don Ayers, Don Vogt

Post Reply
Posts: 71
Joined: Sun Mar 04, 2007 10:05 pm
Location: Lexington, Michigan

KL idle

Post by trebot » Wed Aug 05, 2020 10:47 pm

Have KL with 60 hours on rebuild. Have Ignitor Electronic Ignition, Flamethrower coil and Accell ignition wires. Motor runs great at all speeds. Engine temp 115 to 120 on digital guage.
Problem is after about 2 hours of cruising, the idle is very rough and won' t run under 1000 rpm no load. Carb has been rebuilt with no change.
My intake manifold has coolant water piped from front of exhaust manifold to front of carb mount and out the rear side then to the exhaust elbow. All other KL's I've seen have coolant piped directly from front of exhaust manifold to outlet elbow.
I'm thinking of bypassing the line to carb mount and run directly to elbow. Thinking after motor runs for extended period, some coolant water is leaking into intake manifold, causing rough idle.
Anyone experienced similar problem?

User avatar
Posts: 12
Joined: Thu Jul 02, 2020 6:41 am
Location: Reedville VA

Re: KL idle

Post by matthew.smith » Thu Aug 06, 2020 7:08 am

Manafold leaks can effect all sorts of stuff. Drives me nuts because the way to tell was water in your oil, but not the case. I just replaced the exhaust manifold on my W and it changed everything, smooth running, less smoke, no rough idle. I am not a mechanic, nor an engine expert, or even an engine idiot? In fact I am an artist by trade. Have yoou considered that the color on the KL is wrong? HA. Sorry. The KL is an amazing engine. The after 2 hrs of running thing kinda has me stumped though.
Woody Boater
1948 CC 25' Sportsman - WECATCHEM
1937 CC 16' Special Racer - Stinky
1968 Rice 40 - Trawler - Sweet Pea

User avatar
Posts: 1967
Joined: Mon Nov 14, 2005 12:28 pm
Location: Three Lakes, WI

Re: KL idle

Post by drrot » Thu Aug 06, 2020 11:57 am

The plumbing looks right. There is a chance the heat opens up a crack and water gets in. Pull the copper tubes from the manifold end cap and the elbow. Plug the holes and run it with no water in the intake and see what happens.
You do not have the required permissions to view the files attached to this post.
Jim Staib

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

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest