Yanmar loses RPM in gear - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Chat  
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Diesel
 Not a Member? 


Like Tree3Likes
Reply
 
LinkBack Thread Tools
  #1  
Old 11-26-2013
Junior Member
 
Join Date: Apr 2013
Posts: 11
Thanks: 13
Thanked 0 Times in 0 Posts
Rep Power: 0
shansen5 is on a distinguished road
Yanmar loses RPM in gear

I have about 500 hours on my 3GY20 Yanmar. I've had no problem with it. I've always been able to run it up to 3400 - 3600 RPM. I prefer to run it about 2700 RPM for comfort and vibration, and that seems to optimize speed/efficiency. I try to run it at 3000 periodically to clean the cylinders.

Today I was running it in the bay about 2500 RPM, pushed it up to 2800 as I headed back to the marina. I felt it slow down, looked down at the tach and it was 2500 again. Increasing the throttle made no difference--it wouldn't go past 2500. I can put it in neutral and rev it to 3800, but in gear nothing past 2500.

Any ideas where to start looking?

Thanks.

Steve
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 11-26-2013
Junior Member
 
Join Date: Apr 2013
Posts: 11
Thanks: 13
Thanked 0 Times in 0 Posts
Rep Power: 0
shansen5 is on a distinguished road
Re: Yanmar loses RPM in gear

I should add that I can see the prop in the water and it doesn't have anything wound around it. At least nothing that's visible.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 11-26-2013
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 15,706
Thanks: 96
Thanked 267 Times in 257 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: Yanmar loses RPM in gear

When was the last time you changed a fuel filter?? Could be the early sign of pluggage.. If that's not the issue for sure, perhaps your fuel tank pickup has a screen and it's starting to get gummed up..
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to Faster For This Useful Post:
shansen5 (11-27-2013)
  #4  
Old 11-26-2013
jsaronson's Avatar
Senior Member
 
Join Date: Dec 2011
Posts: 909
Thanks: 5
Thanked 25 Times in 25 Posts
Rep Power: 4
jsaronson is on a distinguished road
Re: Yanmar loses RPM in gear

Dirty bottom or shaft if there is also black smoke.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 11-26-2013
boatpoker's Avatar
Senior Member
 
Join Date: Jul 2008
Location: Toronto
Posts: 1,128
Thanks: 9
Thanked 26 Times in 25 Posts
Rep Power: 7
boatpoker is on a distinguished road
Re: Yanmar loses RPM in gear

Fuel starvation probable
Low compression possible
__________________
Dirt People Scare me
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to boatpoker For This Useful Post:
shansen5 (11-27-2013)
  #6  
Old 11-26-2013
newhaul's Avatar
islander bahama 24
 
Join Date: Feb 2010
Location: bremerton wa
Posts: 1,454
Thanks: 7
Thanked 45 Times in 45 Posts
Rep Power: 6
newhaul is on a distinguished road
Re: Yanmar loses RPM in gear

I concur likely fuel problem filter or possible injector issue check filter then lift pump lastly the injectors
__________________
Illegitimus Non Tatum Carborundum.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 11-26-2013
fryewe's Avatar
Senior Member
 
Join Date: Dec 2004
Posts: 1,400
Thanks: 30
Thanked 48 Times in 48 Posts
Rep Power: 11
fryewe is on a distinguished road
Re: Yanmar loses RPM in gear

I also think it sounds like fuel starvation.

When was the last fuel filter change? If the filter is dirty or fills with water the engine will begin to lose power and be unable to achieve full RPM.

Might check the fuel pickup clear (blow it out using LP air?). Check for a kink in a fuel line.

Good luck.
__________________
"It's not what you know that's important...it's what you do with what you know." -H.G. Rickover
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to fryewe For This Useful Post:
shansen5 (11-27-2013)
  #8  
Old 11-26-2013
Delezynski's Avatar
Senior Member
 
Join Date: Sep 2013
Location: Currently in Az. and trailer to various places.
Posts: 439
Thanks: 12
Thanked 37 Times in 33 Posts
Rep Power: 2
Delezynski is on a distinguished road
Re: Yanmar loses RPM in gear

Steve,

Once you have checked out the fuel supply, check your exhaust mixing elbow.

It clogs up slowly over time and restricts the engine due to back pressure buildup.



Greg
Faster and mitiempo like this.
__________________
Greg & Jill Delezynski
Nor'Sea 27, Guenevere
Home page -
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Youtube page -
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to Delezynski For This Useful Post:
shansen5 (11-27-2013)
  #9  
Old 11-26-2013
mitiempo's Avatar
Senior Member
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,356
Thanks: 0
Thanked 86 Times in 77 Posts
Rep Power: 8
mitiempo will become famous soon enough mitiempo will become famous soon enough
Re: Yanmar loses RPM in gear

What was the exhaust like when you only achieved 2500 rpm in gear? Any black smoke or soot? If so the exhaust elbow's restriction is a likely reason.
__________________
Brian
Living aboard in Victoria Harbour
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to mitiempo For This Useful Post:
shansen5 (11-27-2013)
  #10  
Old 11-27-2013
poopdeckpappy's Avatar
Senior Member
 
Join Date: Jul 2006
Location: San Diego
Posts: 5,939
Thanks: 25
Thanked 41 Times in 35 Posts
Rep Power: 10
poopdeckpappy has a spectacular aura about poopdeckpappy has a spectacular aura about
Re: Yanmar loses RPM in gear

I just serviced one of our charter boats a 3ym30, it had the same issue, I sent the injectors out to be serviced and replaced exhaust elbow now it runs like a champ
__________________
1978 Tayana 37
1955 Blanchard 51 Custom ( I got a woody )
Reply With Quote Quick reply to this message Share with Facebook
The Following User Says Thank You to poopdeckpappy For This Useful Post:
shansen5 (11-27-2013)
Reply

Tags
rpm loss , yanmar

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 2gm20f RPM RobGallagher Diesel 2 06-30-2012 04:24 PM
Yanmar 2GM20F RPM issue cspaniel Diesel 11 05-20-2012 05:01 PM
Yanmar not making RPM Flyyboy Diesel 18 12-26-2009 11:32 AM
more RPM issues - yanmar rperret Gear & Maintenance 5 10-19-2008 08:51 PM


All times are GMT -4. The time now is 04:00 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2015, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.