Yanmar 3GM30F low RPM in forward - SailNet Community
 5Likes
Reply
 
LinkBack Thread Tools
post #1 of 32 Old 02-05-2017 Thread Starter
Senior Member
 
bigdogandy's Avatar
 
Join Date: Jun 2008
Location: Fort Lauderdale, Florida
Posts: 618
Thanks: 8
Thanked 26 Times in 26 Posts
Rep Power: 9
 
Dock
Yanmar 3GM30F low RPM in forward

Hey friends - have a puzzle I'm trying to solve and would like some help......my engine starts up easily and runs great in neutral - smooth and quiet and will rev to 3,000 RPM easily; in reverse runs smooth and will rev to about 2,800 RPM; in forward, however, will only rev to a little under 2,000 RPM.....generates some white / grey smoke at that point but not excessive.

Transmission is Kanzaki KM2P, fluid is topped up and clean. All filters are new.

The problem has developed over the last 6 months or so.....first noticed it when coming in at the end of the day when the engine felt like it was losing some power in forward. Has gotten progressively worse since then.

Any thoughts on cause or things to check out?

Thanks.

Andy
Key Largo
S/V Everlasting Moon
1981 Endeavour 32

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Be joyful though you have considered all the facts.
- Wendell Berry

Last edited by bigdogandy; 02-05-2017 at 05:09 PM. Reason: changed "neutral" to "reverse"....thanks hellosailor!
bigdogandy is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 32 Old 02-05-2017
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 18,771
Thanks: 141
Thanked 499 Times in 473 Posts
Rep Power: 10
     
Re: Yanmar 3GM30F low RPM in forward

Could be a plugged exhaust mixing elbow.. in neutral there's no load and less exhaust volume.

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)
Faster is offline  
Quote Quick Reply Share with Facebook
post #3 of 32 Old 02-05-2017 Thread Starter
Senior Member
 
bigdogandy's Avatar
 
Join Date: Jun 2008
Location: Fort Lauderdale, Florida
Posts: 618
Thanks: 8
Thanked 26 Times in 26 Posts
Rep Power: 9
 
Dock
Re: Yanmar 3GM30F low RPM in forward

Thanks Ron - had cleaned the elbow when the problem first appeared, but maybe I didn't get it all the way cleaned out. Will take another run at that. Seems curious to me the problem only seems to occur in forward, though, and not reverse?

Andy
Key Largo
S/V Everlasting Moon
1981 Endeavour 32

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Be joyful though you have considered all the facts.
- Wendell Berry
bigdogandy is offline  
Quote Quick Reply Share with Facebook
 
post #4 of 32 Old 02-05-2017
Senior Member
 
overbored's Avatar
 
Join Date: Oct 2010
Location: Dana Point, Ca
Posts: 1,887
Thanks: 1
Thanked 124 Times in 123 Posts
Rep Power: 7
 
Re: Yanmar 3GM30F low RPM in forward

Sounds like it is starving for fuel while under load. How many hours on the fuel injectors ? have you replaced the engine fuel filter? how old are the fuel lines? algae in the tank and fuel lines? fuel pickup tube in the tank has blockage?

"FULL TILT II" 2011 BENETEAU FIRST 30
"GOLD RUSH" PRINDLE 16
overbored is offline  
Quote Quick Reply Share with Facebook
post #5 of 32 Old 02-05-2017
Senior Member
 
overbored's Avatar
 
Join Date: Oct 2010
Location: Dana Point, Ca
Posts: 1,887
Thanks: 1
Thanked 124 Times in 123 Posts
Rep Power: 7
 
Re: Yanmar 3GM30F low RPM in forward

only in forward? what type of prop? fixed or ?

"FULL TILT II" 2011 BENETEAU FIRST 30
"GOLD RUSH" PRINDLE 16
overbored is offline  
Quote Quick Reply Share with Facebook
post #6 of 32 Old 02-05-2017
░░░░░░░░░░
 
Join Date: Apr 2006
Posts: 12,305
Thanks: 6
Thanked 176 Times in 173 Posts
Rep Power: 12
   
Re: Yanmar 3GM30F low RPM in forward

"progressively worse"
Barnacles on the prop? (Yum, bouillabaisse!)
hellosailor is offline  
Quote Quick Reply Share with Facebook
post #7 of 32 Old 02-05-2017 Thread Starter
Senior Member
 
bigdogandy's Avatar
 
Join Date: Jun 2008
Location: Fort Lauderdale, Florida
Posts: 618
Thanks: 8
Thanked 26 Times in 26 Posts
Rep Power: 9
 
Dock
Re: Yanmar 3GM30F low RPM in forward

New filters all around, but haven't checked the tank lately for scummage.... Will do that also. Fuel in the racor looks, clear for what that is worth. The injectors have at least 600 hours, as that is how many I've put on the engine over the last 9 years.

3 blade fixed prop, more than 2 years since last haul and paint but I clean it occasionally. Not pristine but not too bad, either. If it were the props wouldn't that affect reverse as well as forward?

Going below to clean to elbow now....love the boat yoga poses this boat makes possible in doing this operation!

Andy
Key Largo
S/V Everlasting Moon
1981 Endeavour 32

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Be joyful though you have considered all the facts.
- Wendell Berry
bigdogandy is offline  
Quote Quick Reply Share with Facebook
post #8 of 32 Old 02-05-2017
░░░░░░░░░░
 
Join Date: Apr 2006
Posts: 12,305
Thanks: 6
Thanked 176 Times in 173 Posts
Rep Power: 12
   
Re: Yanmar 3GM30F low RPM in forward

" If it were the props wouldn't that affect reverse as well as forward?"
Presumably, but I didn't see you mention reverse at all?

The only thing that would affect performance "in forward only" would be a transmission problem. A fouled or unfouled prop would have the same (lack of) effect in both gears. Uless someone taught the barnacles to sing in harmony.(G)
bigdogandy likes this.
hellosailor is offline  
Quote Quick Reply Share with Facebook
post #9 of 32 Old 02-05-2017
Senior Member
 
Join Date: Jul 2006
Posts: 1,711
Thanks: 1
Thanked 65 Times in 62 Posts
Rep Power: 11
 
Quote:
Originally Posted by bigdogandy View Post
Transmission is Kanzaki KM2P, fluid is topped up and clean.
What fluid and at what fill level did you use?

Last edited by aa3jy; 02-05-2017 at 04:12 PM.
aa3jy is offline  
Quote Quick Reply Share with Facebook
post #10 of 32 Old 02-05-2017
al brazzi
 
Join Date: Oct 2014
Location: Lower Chesapeake bay
Posts: 1,477
Thanks: 0
Thanked 49 Times in 49 Posts
Rep Power: 3
 
Re: Yanmar 3GM30F low RPM in forward

Quote:
Originally Posted by bigdogandy View Post
New filters all around, but haven't checked the tank lately for scummage.... Will do that also. Fuel in the racor looks, clear for what that is worth. The injectors have at least 600 hours, as that is how many I've put on the engine over the last 9 years.

3 blade fixed prop, more than 2 years since last haul and paint but I clean it occasionally. Not pristine but not too bad, either. If it were the props wouldn't that affect reverse as well as forward?

Going below to clean to elbow now....love the boat yoga poses this boat makes possible in doing this operation!
You are not trying to go hull speed in reverse so it is very different, plus pitch is different on a fixed prop in reverse. I would clean real good and see what you get.
albrazzi is offline  
Quote Quick Reply Share with Facebook
Reply

Tags
yanmar 3gm

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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 3gm30f low RPM at idle carlager Diesel 10 10-11-2015 02:40 AM
yanmar vibration at low rpm 17spyglass17 Diesel 2 03-04-2014 12:42 PM
Yanmar tach reads low rpm malyea Gear & Maintenance 11 06-05-2013 08:38 AM
Yanmar stalls at low rpm markgoldfarb Diesel 2 06-26-2011 09:48 AM
High RPM = slipping out of forward??? olysailor Atomic 4 10 06-21-2008 09:24 AM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome