Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 05-09-2009, 16:09   #1
Registered User

Join Date: Sep 2009
Boat: Laurin 32
Posts: 2
Yanmar 3gm30, one cylinder runs hard

Hi,

Just found this forum, seems great, so my first contribution before I start asking my question is to show you this site where you can find most workshop manuals for Yamnar engines..
Albin Motor

Ok, now to the more important stuff:
When starting my 3gm30, cyl nbr 3 needs about 15 seconds before it runs smoothly, and when it starts, it runs "harder" then the other two. It like it is knocking harder. I found out that it was cylinder nr 3 by lifting the decompression lever when the engine ran.
For every cylinder the hard sound was still present, but when lifted it for cyl 3, it got more quitet and the engine ran on 1 & 2 but more smootly.

Is this fault mechanical, or can it be so "simple" that it is the fuel pump that delivers wrong amout of fuel to it compared to the other two cylinders? Or something else.
All tips are really welcome..

Best regards
Kalle (sweden)
__________________

__________________
SY_ELIN is offline   Reply With Quote
Old 05-09-2009, 16:44   #2
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
Probably a bad injector

Any smoke?
__________________

__________________
Chief Engineer is offline   Reply With Quote
Old 05-09-2009, 16:45   #3
Senior Cruiser
 
roverhi's Avatar

Cruisers Forum Supporter

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,005
Send a message via Yahoo to roverhi
Mine does the same thing ifI start it with the throttle all the way closed. I ust crack the throttle a little and it starts up smoothly. Haven't specifically tested it but the engine seems to run fine if I retard the throttle to the stops after it starts. It's been doing it for a couple of years and still seems to run strong. Maybe for as long a I've owned the boat as I almost always crack the throttle before starting it. My son discovered the problem when he took the boat out on his own and cranked it over with the throttle against the stops. It did it to me the last time I started it when I didn't advance the throttle before starting.
__________________
roverhi is online now   Reply With Quote
Old 05-09-2009, 16:53   #4
Registered User

Join Date: Sep 2009
Boat: Laurin 32
Posts: 2
No smoke, maybe just when I give full throttle.. but not otherwise.

It doesn't matter how I have the throttle when it starts, idle or max.
It always starts, and it has been like this for 10-13 years accordingly to the previous owner, I just wanted to fix it since Im going on a longer trip in two years from now so.. I want to have it top condition..
__________________
SY_ELIN is offline   Reply With Quote
Old 05-09-2009, 17:15   #5
Registered User

Join Date: Aug 2009
Posts: 211
Quote:
Originally Posted by SY_ELIN View Post
When starting my 3gm30, cyl nbr 3 needs about 15 seconds before it runs smoothly
Smoothly or quietly? If smoothly then I'd suspect the fuel side of things. If quietly then maybe lubrication, or lack of.

Quote:
Originally Posted by SY_ELIN View Post
No smoke, maybe just when I give full throttle.. but not otherwise.

It doesn't matter how I have the throttle when it starts, idle or max.
It always starts, and it has been like this for 10-13 years accordingly to the previous owner
No smoke rules out piston rings, etc. If it always starts and it's been the same for that long then to be honest I wouldn't worry.
__________________
ColdFusion is offline   Reply With Quote
Old 29-09-2009, 20:04   #6
Registered User
 
FloridaWriter's Avatar

Join Date: Jan 2009
Location: Maitland, FL
Boat: Bristol 29
Posts: 230
Is your idle rpm set at 900? If it is set lower it will run very rough.
__________________
David www.bristol29.com
"The lookout that first sights the cat shall have ten guineas and remission of sins, short of mutiny, sodomy, or damaging the paintwork." - Jack Aubrey
FloridaWriter is offline   Reply With Quote
Old 29-09-2009, 20:55   #7
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,781
Injectors

Pull the injectors, you can have a shop test the pressure and check the spray pattern eaisly enough. The most common problem will be a clogged tip caused by running with too little of a load on the engine. When the tips clog the fuel isn't atomized properly, leading to knocking.
__________________
Sailmonkey is online now   Reply With Quote
Old 08-10-2009, 23:21   #8
Registered User

Join Date: Oct 2009
Location: australia
Posts: 467
Kalle,
Possible one of three things -- check. 1. noisey cyl. -injector 2.fuel pump delivery valve 3. leaky valve guide. if fitted with manifold cold start vapour system check element valve.
__________________

__________________
shakey doug is offline   Reply With Quote
Reply

Tags
3gm, 3gm30, yanmar

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
Looking for used Yanmar 2QM20 cylinder head. tylerz Engines and Propulsion Systems 4 04-03-2013 13:24
For Sale: Rebuilt Yanmar YS One Cylinder Chief Engineer Classifieds Archive 4 06-08-2009 22:14
Electric Fuel Pump for Yanmar 3 Cylinder? quartersplash Engines and Propulsion Systems 1 07-06-2009 08:58
Yanmar YS Series Cylinder head with valves Chief Engineer Classifieds Archive 0 06-10-2008 21:40
Hard Starting Yanmar 3GM30 sailcruz Engines and Propulsion Systems 2 15-05-2007 14:47



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:24.


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.