Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 05-06-2010, 12:35   #16
Senior Cruiser
 
Captain Bill's Avatar

Cruisers Forum Supporter

Join Date: Apr 2008
Location: On the boat
Boat: Endeavourcat Sailcat 44
Posts: 2,313
TexSail has probably got it. A small air leak downstream of the carb will cause this problem. It seems you have the carb pretty well covered though it is possible you will need to have the carb put in an ultrasonic cleaner to be sure. I once had a similar problem and nothing I could do with compressed air and solvent could get those really small idle ports clean. I finally took it to the local shop and he put it in an ultrasonic cleaner for a couple of hours and that took care of it. Fortunately the local shop is very good and only charged me $75 including reassembly and testing.
__________________

__________________
Captain Bill is offline   Reply With Quote
Old 05-06-2010, 13:08   #17
Registered User

Join Date: Dec 2008
Location: ontario canada
Boat: grampian 26
Posts: 1,743
Vaccuum in the intake

There is very little vacuum at wide open throttle. Vacuum is greatest when the throttle plate is closed.
__________________

__________________
perchance is offline   Reply With Quote
Old 05-06-2010, 14:21   #18
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Quote:
Originally Posted by starfish62 View Post

How would I check for bad reed valves? Can they be cleaned like the ports? Or must they be replaced?
I don't remember. Dimensions and clearance measurements I think.
__________________
Therapy is offline   Reply With Quote
Old 05-06-2010, 14:25   #19
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Quote:
Originally Posted by TexSail View Post
Check the gaskets and fasteners on the carburetor and any intake manifolds. I had an old Johnson with exactly the same symptoms of which you speak. There was a bad seal from carburetor to block. At full throttle, the high vacuum would suck the carburetor closer to the block and seal the leak and the motor would run great, but let off the gas and the leak opened up allowing air in leaning out the mixture and necessitating choking the engine to run. Any loose fitting on an intake manifold could cause the same problem.
Dang, I forgot that one.

Gettin' old...........
__________________
Therapy is offline   Reply With Quote
Old 05-06-2010, 15:09   #20
Registered User

Join Date: Sep 2007
Posts: 298
Check any vacuum lines too. An old line will sometimes develop an air leak which will close at higher RPMS. IMHO, it is instructive that the motor seems to be running lean at low RPMS but OK at full throttle.
__________________
TexSail is offline   Reply With Quote
Old 06-06-2010, 18:03   #21
Senior Cruiser
 
starfish62's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Palm Beach, Florida
Boat: Gulfstar 44 Sloop
Posts: 647
Images: 4
Update and THANKS ALL!!! Sat down yesterday and completely dismantled the carb and fuel pump and soaked everything in brake cleaner--NAPA happened to have it on sale for next to nothing so I saved a few bucks--blew compressed air through EVERY port, replaced the float bowl and intake gaskets and then put it all back together. Engine now starts effortlessly without choke and idles smoothly. The whistling sound also seems to have disappeared. My only issue is that, once started, the dinghy seemed to go directly to the Tiki bar on Saturday nite; though it did, several hours later, unerringly return to the big boat which is a puzzle as I have no recollection of driving back! Again, thanks to everybody for helping brainstorm the problem. Now if anyone has any ideas as to how to prevent the dinghy from going to the Tiki bar I would be all ears.
__________________
Starfish
starfish62 is offline   Reply With Quote
Old 06-06-2010, 20:08   #22
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Quote:
Originally Posted by starfish62 View Post
Now if anyone has any ideas as to how to prevent the dinghy from going to the Tiki bar I would be all ears.
That one I have never been able to figure out.
__________________
Therapy is offline   Reply With Quote
Old 06-06-2010, 20:14   #23
Registered User
 
Stillraining's Avatar

Join Date: Oct 2008
Location: Puget Sound
Boat: Irwin 41 CC Ketch
Posts: 2,876
Hide wallet on return...Dingy wont remember where
__________________
"Go simple, go large!".

Relationships are everything to me...everything else in life is just a tool to enhance them.
Stillraining is offline   Reply With Quote
Old 06-06-2010, 21:30   #24
Registered User

Join Date: May 2008
Location: daytona beach florida
Boat: csy 37
Posts: 2,844
Images: 1
i had an experience similar to 'phillsboat'.

motor would run very roughly if at all, and i couldn't find the problem. sadly, even the local yamaha dealer couldn't fix it for a more than a few minutes. kept telling me stories about ethanol in gasoline and how the problem could take many visits to fix (cost me two visits and two hundred bucks).

then, on a hunch, i rebuilt the fuel pump - about twenty bucks for gaskets/membranes.

end of problem.
__________________
onestepcsy37 is offline   Reply With Quote
Old 28-06-2010, 00:55   #25
Registered User
 
mangomuffins's Avatar

Join Date: May 2007
Location: Bradenton Beach, Florida
Boat: 27' Albin Vega - mangomuffins
Posts: 277
thanks starfish!!

Thanks Starfish!!!

Just lo0gged on to see if I could find my "particular" problem and there you have it... hope the solutions work too

Hope you guys are well... maybe you should get over here and see OUR beaches before BP arrives they are stiil clean!!!


cheers all

mm
__________________
mangomuffins is offline   Reply With Quote
Old 28-06-2010, 06:41   #26
Senior Cruiser
 
starfish62's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Palm Beach, Florida
Boat: Gulfstar 44 Sloop
Posts: 647
Images: 4
Hi MM, good to hear from you. Let's hope the oil is taken by the ocean currents to the place where it is least destructive.

If you rebuild the carb, put a little something tacky--like some permatex--on the idle jet plug as it has a little pressure on it and needs to stay in place.

Quote:
Originally Posted by mangomuffins View Post
Thanks Starfish!!!

Just lo0gged on to see if I could find my "particular" problem and there you have it... hope the solutions work too

Hope you guys are well... maybe you should get over here and see OUR beaches before BP arrives they are stiil clean!!!


cheers all

mm
__________________
Starfish
starfish62 is offline   Reply With Quote
Old 28-06-2010, 09:34   #27
Registered User
 
Sunspot Baby's Avatar

Join Date: May 2003
Location: New Bern, NC
Boat: Prout Manta 38' Catamaran - Sunspot Baby
Posts: 1,521
Images: 14
Did you replace the hose from the fuel tank to the engine? Mine wants a new one every year or two.

George
__________________

__________________
She took my address and my name
Put my credit to shame
Sunspot Baby, sure had a real good time
Bob Seger
Sunspot Baby is offline   Reply With Quote
Reply

Tags
fuel, fuel starvation, outboard

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Challenge: Wake Up The Mechanics - Outboard Challenge Ex-Calif Challenges 37 04-04-2016 09:55
Volvo D2 Diesels - Fuel Starvation rickfant Engines and Propulsion Systems 23 31-12-2015 13:30
Running Fuel Out of an Outboard Captain Bill Auxiliary Equipment & Dinghy 25 08-07-2010 20:23
Hey, Yanmar Mechanics! Fuel Lift Pumps ! Chief Engineer Engines and Propulsion Systems 14 03-05-2010 09:08
Rebuilding Outboard Fuel Tank b-rad Auxiliary Equipment & Dinghy 2 12-02-2010 12:13



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:10.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.