Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-10-2014, 09:15   #1
Registered User

Join Date: Jan 2013
Location: Whitby, Canada
Posts: 18
Question Strange engine problem

Hi all.

My sailboat has a Westerbeke 42B4 diesel engine.
It starts normally, and can run for hours at cruising speed. Later, when I need to wait for as bridge opening, I would witch between neutral and idle speed for some time. Then, when bridge opens, I would press ahead, but the RPMs wild slowly drop and engine stops. Even at full throttle. Sometimes RPM would fluctuate without giving full power.
Restarting the engine sometime fixes the problem temporarily, until the next bridge...
Very frustrating.

More info:
- In neutral, the RPMs are holding fine, the problem is when engine is engaged.
- Fuel filters are freshly replaced and clean
- Tightened all fuel line clamps, etc. - fuel and air leaks are unlikely.
- Prop is clean

Any suggestions will be greatly appreciated.

Thanks.
__________________

__________________
argalax is offline   Reply With Quote
Old 11-10-2014, 10:02   #2
Marine Service Provider

Join Date: Jan 2014
Posts: 49
Re: Strange engine problem

Check that plenty of fuel is reaching your nearest filter to the fuel tank. If the filter does not have a bowl on the bottom that you can shine a light through then add some clear fuel line near it to confirm you dont have a problem with the pick-up tube in the tank. Then confirm plenty is reaching the lift pump and/or injector pump. When filters are changed be sure there is not a problem with the o-rings, there shouldn't be any drips or runs. When was the last maintenance done? When was your fuel tank last cleaned? There might be old contaminated fuel giving you problems. Injectors may need to be pulled and tested.
__________________

__________________
CptLawrence is offline   Reply With Quote
Old 11-10-2014, 20:46   #3
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Strange engine problem

It sure sounds like a fuel problem, but the first thing that came to mind was the shut off solenoid.
Check the wire that keeps the fuel solinoid open. It may be loose at one end or the other, or even about to break somewhere in between.
When your running hard it keeps enough current but a slowdown allows it to lose contact.

Another item maybe the freshly changed fuel filer is sucking air into the system and while running slow there's not enough fuel to get going again.

One more thing to check is the mixing elbow, it maybe getting plugged. All suggestions, it's a process of elimination.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 13-10-2014, 08:20   #4
Registered User

Join Date: Jan 2013
Location: Whitby, Canada
Posts: 18
Re: Strange engine problem

Thanks for the replies - helpful.
Looks like I have to clean the fuel tank - primary filter seem to collect sludge quickly.
__________________
argalax is offline   Reply With Quote
Old 13-10-2014, 08:40   #5
Registered User

Join Date: Oct 2014
Location: Toronto
Boat: Corbin 39
Posts: 10
Re: Strange engine problem

There's a thread on this over at YBW. A small airleak seems like a common problem, sucking in more air under load. Air intake blockage might be another thing to consider, should lead to black smoke though.

Good luck,
Crow
__________________
S/V Two Crows - Toronto, Canada
Crow is offline   Reply With Quote
Old 13-10-2014, 08:48   #6
Registered User

Join Date: Oct 2009
Location: Naples, Florida, USA
Boat: Dean 400, 40' catamaran, Daruma
Posts: 124
Re: Strange engine problem

Once upon a time I had a similar problem, let off the fuel and the engine quit, neutral - restart fine - put into gear quit. Put into gear and accelerate fast and may or may not go. Had a rope wound around the prop on that sail drive so tight that it was real hard to remove. Had noticed an ever so slight but not usual vibration at cruise rpm.
__________________
dlockhart is offline   Reply With Quote
Old 13-10-2014, 19:08   #7
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Re: Strange engine problem

Quote:
Originally Posted by argalax View Post
Thanks for the replies - helpful.
Looks like I have to clean the fuel tank - primary filter seem to collect sludge quickly.
That'll do it.
__________________
John
SkiprJohn is offline   Reply With Quote
Old 23-10-2014, 20:20   #8
Registered User

Join Date: Jan 2013
Location: Whitby, Canada
Posts: 18
Re: Strange engine problem

Just an update.
Quote:
Originally Posted by SkiprJohn View Post
That'll do it.
Yes, it did. Cleaned the tank (there was quite e bit of sludge), replaced fuel filters - didn't have problem since.
__________________
argalax is offline   Reply With Quote
Old 23-10-2014, 21:36   #9
Registered User
 
Sailorman Ed's Avatar

Join Date: Jun 2010
Boat: Polynesia 40/42
Posts: 685
Images: 15
Send a message via Skype™ to Sailorman Ed
Re: Strange engine problem- Yanmar

Argalax - glad you found your problem.

I have twin 2 cyl Yanmars, 600 hours, . Brought the boat (new to me) from MD to NC, both engines ran perfectly. Been sittingin a marina fixing other issues, went to take the family out last WE, one starts right up while the second would not fire up. Switched batteries thinking maybe not enough juice - no difference. Used the compression release levers to get one cyl to fire and then would quit. Bleed the fuel lines to the injectors, still no good. Left with 1 engine. Next day moving to a different anchorage, wife says, try the engine, maybe it will work now. I said nothing changed but would give it a try - STARTED RIGHT UP!!!! Ran fine the way back. So what should I be looking for? Runs perfectly while running, has fuel to the injectors, has compression...what am I missing?
Ed
__________________
Sailorman Ed is offline   Reply With Quote
Old 24-10-2014, 04:59   #10
Marine Service Provider

Join Date: Jan 2014
Posts: 49
Re: Strange engine problem

Sounds like it was warmed up by the other engine's heat or maybe the day was warmer. Older diesels with less compression need that heat. Have you checked the glow plugs? They should get power when you turn on the key or turn it backwards or push a button.
__________________

__________________
CptLawrence is offline   Reply With Quote
Reply

Tags
engine

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
Strange Theory about Engine Overheating Moody46CC Engines and Propulsion Systems 23 24-08-2014 19:11
Strange ST4000+ problem maersi Marine Electronics 2 10-12-2013 03:12
A Strange Problem with a Desktop PC and an Inverter sdowney717 Marine Electronics 9 27-08-2011 09:59
I Have a Strange Form of Agorophobia fujiwara takumi General Sailing Forum 18 26-07-2009 09:12
Strange Body Of Water? CaptainK Pacific & South China Sea 21 01-03-2006 13:04



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 12:31.


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.