On one of my engines (1967 427, port side), I have noticed what looks to be fuel out the exhaust at very low (idle) speed. I can't tell for sure, but it looks more like fuel than oil to me.  Just a slight boost in RPM and it stops doing it.  Could it be a mixture adjustment on the carburetor providing excess fuel at the low rpms? If it isn't fuel, I guess it could be oil, but we use very little oil over the course of a season in either engine, although occasionally there is some smoke, again noticeable at low rpm. The engine seems to run very well otherwise.  This is the engine that had the plug wires installed to several of the wrong plugs before I got it.  Any ideas would be appreciated. 

Views: 490

Reply to This

Replies to This Discussion

Hi Tim....good to know. I am in no way a mechanic so I will have that looked at. This is the first I have heard of this so I am glad you chimed in. Dick, I am not sure if you are responding to the original post or mine but this is when I fire up and idle. I did not really get a chance to run her last year to check if it does it warmed up as I had other issues. So I can't answer as to does it do it while running all day. Tim, is that something you have to take apart the engine? As I said, I am not a mechanic. Thanks all.

I'm replying to the original post. There are 2 things to consider here. First, on a running, idling, warmed up engine with the choke valve wide open, remove the flame arrestor and shine a flashlight down into the running, idling carb. If you see any liquid fuel anywhere, you have a problem and definitely are rich at idle. The carb needs to see a doctor. The problem usually is a leaking needle & seat or leaking secondary diffuser gaskets. If all is well here, the problem may be a plugged exhaust crossover passage in the intake manifold. There is a passage in the intake manifold that runs from one bank to the other and exhaust flowing through this passage heats the manifold floor right directly under the carb. The purpose of this is to warm the incoming fuel air charge and aid in atomizing it. At higher engine speeds, the velocity of the air fuel mixture flowing through the manifold does a pretty good job of atomizing incoming liquid fuel droplets, along with the heat of a fully warmed up engine. But at a cold idle if this passage is clogged with carbon ( a very common occurrence) you're going to see a sheen from the exhaust water. On our previous 38 both engines did this when cold, but after a run on the lake when I came back to dock the sheen was no longer present as the heat in the engines were atomizing the fuel. Both of my crossover passages were plugged. When I did a valve job on the port engine, a plumber friend with a small power snake was able to break through the blockage AFTER I had soaked the passage with carburetor cleaner (nasty stuff) for 2 days. Upon engine reassembly, you could actually feel the passage portion of the intake manifold heating up and the sheen form that side was gone.

There could also be other reasons for a sheen, but these 2 are really common.

Reply to Discussion


Club News

2019 Wall Calendars Now Available!!

The Chris-Craft Commander Club 2019 Wall Calendar is now available!!.  We're having to do things a little differently this year, so for calendar details & ordering, Click Here


2018 Photo Contest Winner

The 4th Annual Chris-Craft Commander Club Photo Contest had more than 50 entries and selecting the winners was not an easy task. 

First place: submitted by Pat Chaps

Second place: submitted by Martin Krall;

Third place: submitted by Jeff Pacy.

To view all entries to this year's contest,         Click Here


The 2018 Chris-Craft Commander Club National Rendezvous is in the books and it was a great time!!

City of Mentor, Ohio

The city of Mentor, Ohio and the Lawnfield Inn & Suites were wonderful hosts.  A special Thanks to Rob Kneen, the local member sponsor, and Char Pike for the hours of hard work put in organizing and coordinating an amazing weekend. 

The Rendezvous Photo Albums can be accessed through the links below, as well as, under Library, Photo Albums.  We will continue to add links to other albums as they become available. Also below, you will find links to a couple articles written for the local newspaper.

Photo Album 1                 Photo Album 2  

Photo Album 3


Chris-Craft Commander Club Celebrates Anniversary in Mentor

Chris-Craft Commander connoisseurs congregate at Mentor Lagoons Marina



© 2018   Created by CCCC Webmaster.   Powered by

Badges  |  Report an Issue  |  Terms of Service