Vaporizing Fuel

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

Vaporizing Fuel

Postby quitchabitchin » Tue Jun 07, 2016 8:18 pm

I've been fighting a fuel issue and am totally baffled this evening. Here's the story -

After a full engine build, the boat ran great, idled great, but would lose fuel pressure above 2800 RPM. I installed a pressure gauge and verified that the pressure was dropping. I rebuilt the mechanical fuel pump and seemed to solve the problem. The boat ran real good and would run wide open up to 4200 RPM and maintain good pressure (4-5psi). Then one day, it started sputtering while in a turn and died. It wouldn't restart. It was backfiring through the carb(fuel related), and seemed to be vapor locked. It started right up and ran good in the driveway once it cooled off.

Last year at Algonac, I started it, let it run a few minutes on the trailer, and after about 5-10 minutes, it died and wouldn't restart. Same symptoms, sputtering, backfiring, etc. I blamed it on ethanol fuel boiling as I could hear it sizzling in the carburetor. I replaced the mechanical pump with an electric one, and didn't get back out last year due to my big house project consuming the rest of Summer. I started it to Winterize it, but that was it.

I brought it home yesterday and started it tonight. It started fairly easily, but ran a little rough, then seemed to straighten out and was running pretty good. After a couple starts and restarts, it would barely idle and quit running again. It wouldn't restart and acted the same way again. I took the flame arrestor off and there was fuel vapor coming out of the primaries and the secondary flaps were completely closed and covered in fuel. I tried to start it again and it was the same issue, vapor in the primaries and fuel would bubble out of the secondary squirters and cover the secondary flaps. It seems like it was vaporizing/boiling fuel again, but nothing was hot, I could touch the intake, exhaust, block, risers, everything without much problem. After Algonac last year, I siphoned the entire tank and drained it nearly dry and put fresh Shell gas in it yesterday, so I don't think it's a gas issue.

Why would the carb be getting so hot with such little running time on it? Would a bad PCV valve allow hot air to flow into the base of the carb? I'm grasping at straws here, but don't know what else to do and need to get it fixed before going to Algonac, I'm leaving for Northern Michigan on June 15 and spending the week before the show at my in law's cottage.

Any thoughts?
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jim g » Tue Jun 07, 2016 10:40 pm

Are you running pertronix ignition with a pertronix coil?
jim g
 
Posts: 903
Joined: Wed Dec 14, 2011 10:55 pm

Re: Vaporizing Fuel

Postby quitchabitchin » Wed Jun 08, 2016 5:38 am

Electronic ignition.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jim g » Wed Jun 08, 2016 7:04 am

quitchabitchin wrote:Electronic ignition.


If your using a pertronix coil. Change it. I have had 3 go bad so far this summer. All less then a year old. I've been replacing them with a napa IC14.

The symptoms of their coil failing are the same as the ones your describing. It could also be the ignitor it self. But I would try the coil first. If it still doesn't run right put the points back in it. If it still has running problems after that then you know its in the fuel system.

What carb are you running? Has it been rebuilt? It sounds like it could be running rich or a float might have gone bad.

One of the best carb shops is close to you.

Chris's carb shop in Dayton, Oh.

One last thing. Does your intake have the exhaust chamber underneath the air intake. If so make sure it hasn't opened up to the intake chamber under the carb. You can test it by taking a big flat blade screwdriver and tapping the whole area under the carb.
jim g
 
Posts: 903
Joined: Wed Dec 14, 2011 10:55 pm

Re: Vaporizing Fuel

Postby quitchabitchin » Wed Jun 08, 2016 7:23 am

I'm using a newer Mallory coil and haven't had any issue with it.

The Q manifold doesn't have the exhaust chamber under the carb, the choke tube is in the exhaust manifold. The carb has been rebuilt, I'll have to pull it apart and check the floats and needle/seats to make sure they're set correctly. It seems very rich to the point of flooding. I'll start with the carb settings tonight.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jfrprops » Wed Jun 08, 2016 8:36 am

Andy,

I know this sounds like fuel related....but I second the comments on the coil.

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)
jfrprops
 
Posts: 1926
Joined: Thu Dec 29, 2005 10:41 pm
Location: Powhatan Courthouse Virginia

Re: Vaporizing Fuel

Postby quitchabitchin » Wed Jun 08, 2016 9:21 am

It's definitely fuel related since it is percolating fuel through the secondary shooters. I think it's flooding. I'm going to check the floats and needle settings again. I have the old needle and seats, I might switch them out.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jim g » Wed Jun 08, 2016 9:58 am

quitchabitchin wrote:It's definitely fuel related since it is percolating fuel through the secondary shooters. I think it's flooding. I'm going to check the floats and needle settings again. I have the old needle and seats, I might switch them out.


If you have any questions call Chris at Chris's carb shop. He's a nice and very helpful guy. They did an excellent job on Miss America IX carbs this winter.
jim g
 
Posts: 903
Joined: Wed Dec 14, 2011 10:55 pm

Re: Vaporizing Fuel

Postby quitchabitchin » Wed Jun 08, 2016 4:39 pm

Great recommendation on Chris's Carb Shop. I took my carb in today and they put it on a test engine. Before they even attempted to start it, it was flooding, so they took it off. Chris disassembled it in about 3 minutes, finding a piece of dirt in the seat, not allowing the needle to close. He found a couple other smaller issues and is now rebuilding it. He has a test 396 to run it on and said it will be dialed in and ready to go next week. Hopefully, I can bolt it on and go. Thanks for the recommendation Jim.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jim g » Wed Jun 08, 2016 4:47 pm

No problem.

I'm leaving for Akron in the morning and will be there for a week and half. If you were closer I'd come by to see your boat.

Did you tell Chris Miss America sent you?
jim g
 
Posts: 903
Joined: Wed Dec 14, 2011 10:55 pm

Re: Vaporizing Fuel

Postby quitchabitchin » Wed Jun 08, 2016 5:24 pm

I did. He know all about it and told me about the video you sent him. He knows his stuff and I'm sure mine will be good to go when I get it back.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby quitchabitchin » Sat Jun 11, 2016 9:41 am

I got a call from Chris today, complete with the 396 running on my carb in the background. He said it runs perfectly and will be great on my engine. I'll pick it up Monday. Pretty quick turnaround and reasonably priced. I would have to say I'd recommend Chris to anyone here looking for carb work.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jim g » Thu Feb 16, 2017 9:10 pm

How did it run after you got it back?
jim g
 
Posts: 903
Joined: Wed Dec 14, 2011 10:55 pm

Re: Vaporizing Fuel

Postby quitchabitchin » Fri Feb 17, 2017 2:21 pm

After having the distributor rebuilt and timing dialed in, it ran like a fire breathing demon!

Watch the holeshot at the 1:54 mark on this video. Plenty of giddyup.

https://www.youtube.com/watch?v=Ly7wI5zqtPI
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q

CCABC Board of Directors Member
User avatar
quitchabitchin
 
Posts: 568
Joined: Tue Dec 02, 2008 9:48 pm
Location: Oxford, OH

Re: Vaporizing Fuel

Postby jfrprops » Fri Feb 17, 2017 3:53 pm

Andy!

It that you? Is that my old 327 kicking up like that? wow! great vid.

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)
jfrprops
 
Posts: 1926
Joined: Thu Dec 29, 2005 10:41 pm
Location: Powhatan Courthouse Virginia


Return to Fiberglass - Engines & Powertrain

Who is online

Users browsing this forum: No registered users and 1 guest

cron