Active Active   Unanswered Unanswered

Rough starting with an M

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

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Rough starting with an M

Post by JimF » Sat Jul 30, 2016 4:15 pm

For the last few weeks my M engine starts but is rough and kind of pops. If I accelerate in neutral at the dock it stalls. After 10 minutes it is warm and runs like a champ. I tried adjusting the idle mix screw but it makes no difference. It is out about one and a half but all the way in or out several turns makes no difference. Also played with timing with no good results. It bothers me that the idle mix screw does nothing. Can I pull that and look to see what is going on? I hate to mess with an engine that is running good for the most part. I could just let it warm up while I am loading passengers and supplies.
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sat Jul 30, 2016 6:51 pm

"I hate to mess with an engine that is running good for the most part. I could just let it warm up while I am loading passengers and supplies"
That's my advice... also, how do u use the manual choke?
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sat Jul 30, 2016 8:53 pm

I pump the fuel pump and then go full choke for the first attempt. It fires and I push the choke in. It usually starts but runs badly and pops. If I try to accelerate it stalls above 1500. I take the boat out and gradually increase RPM. As long as I take my time I can get it up to max RPM after a while. I can live with this but it is not right
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sun Jul 31, 2016 6:37 am

After it fires, try pushing the choke only half way in. It needs more choke until it warms up a bit. Opening it all the way will starve most engines. After it warms a bit, open it all the way.
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

jim g
Posts: 1003
Joined: Wed Dec 14, 2011 10:55 pm
Contact:

Re: Rough starting with an M

Post by jim g » Sun Jul 31, 2016 9:26 am

Since moving the idle screw doesn't do anything. That means the idle circuit in the carb is stopped up. Also since it stalls out when you accelerate that means the accelerator pump circuit is stopped up. If it all of a sudden started running bad. My opinion is you got a load of trash in your fuel when you filled up. Or a lot of old trash has come loose and done the same thing.

I would recommend rebuilding it. You only have the high speed circuit left. Thats what you are running on.

jfrprops
Posts: 2092
Joined: Thu Dec 29, 2005 10:41 pm
Location: Powhatan Courthouse Virginia
Contact:

Re: Rough starting with an M

Post by jfrprops » Sun Jul 31, 2016 9:39 am

Jim-g has nailed it.....clean that sucker out.

John in Va.
1980 Fairchild Scout 30
19?? custom Argentine Runabout 16'
1954 Whirlwind deluxe dual ckpt 16'
1921 Old Town Charles River 17' (founding Captain, James River Batteau Festival)

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sun Jul 31, 2016 10:31 am

You may be right, but I suggest the choke first...simple, easy and it may work. Then on to more complicated things.
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
dag55
Posts: 70
Joined: Mon Dec 01, 2014 11:49 am
Contact:

Re: Rough starting with an M

Post by dag55 » Sun Jul 31, 2016 11:40 am

The idle mix screw makes no sense before the engine is fully warmed up.
Cavalier 36' Seastrake 1967 "CillaGreta III"
http://chris-craft.org/registry/viewboa ... at_id=2318

martinfeletto
Posts: 32
Joined: Mon Jan 01, 2007 5:03 pm
Contact:

Re: Rough starting with an M

Post by martinfeletto » Sun Jul 31, 2016 12:54 pm

Jim - try running some Sea Foam - it really cleans things up. I buy it at Wal Mart.

Marty

User avatar
mfine
Posts: 1405
Joined: Sun Jun 06, 2010 8:16 pm
Location: Pittsford and Penn Yan NY

Re: Rough starting with an M

Post by mfine » Sun Jul 31, 2016 1:06 pm

Seafoam helps with certain kinds of deposits, but once a path is blocked, it won't get in there to work, so it is likely too late. Also, it does not disolves many types of contamination so don't expect miracles.

I would start by adding a spin on fuel filter and then a carb disassembly and cleaning. Inspect and clean the fuel tank as well. It is also probably a good time to inspect the spark plugs.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sun Jul 31, 2016 2:11 pm

I do have a spin on fuel/water separator but it has not been changed in a long time so I will do that. Also I can not remember the last time I changed the plug so I will do that as well. To clean the carb do I just carefully remove the screws and separate the top and bottom? Then take things apart and flush with carb cleaner? Make sure the pump is free as well as the float? Do I need a rebuild kit or can I just try the cleaning? Sounds like something I can do. Maybe then add the Seafoam to the gas.Thank you all and "Old Paint" says thank you!
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

jim g
Posts: 1003
Joined: Wed Dec 14, 2011 10:55 pm
Contact:

Re: Rough starting with an M

Post by jim g » Sun Jul 31, 2016 2:15 pm

You need a rebuild kit. Most of the gaskets don't survive coming off.

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sun Jul 31, 2016 5:27 pm

I suggest that if you never took a carb apart that you get a pro. Also, did you try using the choke correctly? You may not have an issue at all
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sun Jul 31, 2016 5:53 pm

I have owned this boat for 25 years and have had the engine rebuilt twice. It has been consistently the best starting boat i have ever owned. I would pull the choke all the way and crank and it would fire almost immediately. I would then go to half choke and it would start. I would then push choke in and it would idle perfectly. I think that it safe to say choke is not the issue particularly since the idle mixture screw does nothing either cold or hot.
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sun Jul 31, 2016 6:06 pm

I was not trying to insult or offend you, It had sounded like you were simply opening the choke immediately after it fired. Now the next step is that the carb will have to be rebuilt.
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sun Jul 31, 2016 6:47 pm

Thanks Tom. I did not mean for that to sound like I was taking offense. I will order a rebuild kit and get this taken care of.
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sun Jul 31, 2016 6:55 pm

No worries mate...texting doesnt always convey how we mean things! I try to keep in mind that a new owner will be reading these posts so I try to not be too much of a know-it-all but Im not always successful!
Best of luck!
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sat Aug 27, 2016 4:23 pm

Final report. New spark plugs and professionally rebuilt carb. I installed it today and starts and runs like a champ. Before you install one of these, make sure all the old gasket is cleaned from the manifold. Just saying. I probably needed a practice install anyway!
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

boat_art
Posts: 556
Joined: Sun Feb 12, 2012 6:09 pm
Location: United States
Contact:

Re: Rough starting with an M

Post by boat_art » Sat Aug 27, 2016 5:28 pm

Good news Jim! Enjoy!
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

User avatar
tkhersom
Posts: 983
Joined: Wed Feb 27, 2013 6:56 pm
Location: Edgecomb, Maine
Contact:

Re: Rough starting with an M

Post by tkhersom » Sun Aug 28, 2016 7:07 am

Glad you have her going well again. :D

As a side note. With the Zenith up draft carbs I like to get the engine turning over on the starter before pulling the choke out. I find this allows the intake air to be flowing through the carb before the fuel is introduced by applying the choke. Pulling the choke on before tuning the engine over has at times created a flooding situation for me.

PS: Jim you are a talented man you should rebuild a Zenith one time just for the experience, and I like to clean them using an ultrasonic cleaner.
Troy in ANE - Former President CCABC

1957 CC 21' Continental "Yorktown" (Mom's boat)
https://www.chris-craft.org/boats/22625/
1985 Formula 242LS "Gottago"
1991 Formula 36PC "Band Aids"

Life Is Too Short To Own An Ugly Boat

User avatar
mfine
Posts: 1405
Joined: Sun Jun 06, 2010 8:16 pm
Location: Pittsford and Penn Yan NY

Re: Rough starting with an M

Post by mfine » Sun Aug 28, 2016 10:42 am

Sounds like it was dirt in the carb. Keep the spin on filter fresh to hopefully prevent a repeat in the future.

User avatar
JimF
Club Executive Team
Posts: 637
Joined: Mon Nov 14, 2005 10:48 am
Location: Austin, TX
Contact:

Re: Rough starting with an M

Post by JimF » Sun Aug 28, 2016 11:17 am

It actually was a piece of the screen from the fuel inlet.
1930 Chris-Craft Model 100 20' "MOXIE"
1940 Chris-Craft Red and White 25' "Old Paint"
1946 Chris-Craft Sportsman 25' "CinCity"

Post Reply

Who is online

Users browsing this forum: No registered users and 14 guests