3GM yanmar hard starting - SailNet Community

   Search Sailnet:

 forums  store  

Quick Menu
Boat Reviews  
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Hatches and Portlights
Interior And Galley
Marine Electronics
Other Items
Plumbing and Pumps
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here

Go Back   SailNet Community > On Board > Gear & Maintenance > Engines > Diesel
 Not a Member? 
Old 04-03-2011
Junior Member
Join Date: Oct 2008
Posts: 2
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
sailor5017 is on a distinguished road
3GM yanmar hard starting

I am helping a friend with his 92 era 3gm in a 1992 35.5 hunter. I have had a similar engine in a 1991 37.5. My 37.5 3gm always started very quickly, hardly turning over on starter before firing up on all 3cylinders. My buddies engine started the same untill about two years ago when at times when stated after sitting for a day or two, it required a lot of cranking and eventually started running, roughly for 30seconds or so with a fair amount of black smoke. We have been trying different things to solve this startin problem the things that have been done are:
mixing elbow change, clean fuel filters , new injectors, injector pump rebuild, new hight pressure steel lines from injector pump to injectors, compression check ( within limits) we now notice fuel weep from the area of the injectors where the high pressure steel lins is attached, found by using paper towel blotting after running engine for 15 mins or so. we are fairly sure that this may be the cause of this agravating problem We are wondering how tight should this compression coupling be torgued down? And has anyone had this type of problem and actually solved it?
The engine still behaves the same hard stating after sitting for a day , but runs fine when warmed up. Starts fine unless it sites for a day. I did find a post from a fellow who had the same experience in 2008 but solution to the problem was never posted on this forum.
Reply With Quote Quick reply to this message Share with Facebook
Old 04-03-2011
Senior Member
Join Date: Nov 2002
Posts: 146
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
ereiss is on a distinguished road
hard starting 3gm after few days

I had a similar problem with long cranking after the boat had sat for a few days. My problem ended up being a slight air leak in the secondary filter bleed screw. The washer (assuming it is the copper one) needs to be replaced each time you bleed it. I ended up going to a nylon washer. Problem (at least for me) solved.

Also find that putting the gear in neutral and moving the throttle to give it more fuel also helped getting it to start.

Ed Reiss
Being There
Freedom F38 #154
out of Marion, MA
Reply With Quote Quick reply to this message Share with Facebook
Old 04-04-2011
Irrationally Exuberant
Join Date: Jul 2007
Location: Northern Virginia
Posts: 1,324
Thanks: 8
Thanked 6 Times in 6 Posts
Rep Power: 8
arf145 is on a distinguished road
Fuel leak will do that, and like ereiss said, that bleed screw washer can be the problem. Just don't do what my PO did and crank that screw down harder--you'll just strip out the threads in the aluminum filter housing. Since you just replaced the high pressure lines and injectors and now see a weep there, I wouldn't think that was your original cause.
Tom K

2000 Beneteau 331
Northern Chesapeake Bay

Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright
Reply With Quote Quick reply to this message Share with Facebook
Old 04-07-2011
Senior Member
Join Date: Oct 2006
Location: Virginia
Posts: 725
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
badsanta is on a distinguished road
After sitting my 3gm30f does the same. I flip the decompression levers on, put it in neutral, give it almost full throttle and crank it for 3-4 sec. Then turn off the decompression levers, return throttle to slow turn on the cooling water intake and crank to start. Usually starts right up, If I just try to start it without doing this first it won’t.
I would also replace your copper crush washers.
That derelict boat was another dream for somebody else, don't let it be your nightmare and a waste of your life.
Reply With Quote Quick reply to this message Share with Facebook

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


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 starting question nk235 Gear & Maintenance 29 04-19-2009 06:35 PM
Starting Battery - Yanmar 3GM JohnRPollard Gear & Maintenance 14 03-11-2008 12:31 PM
Trouble Starting my Yanmar 1GM bullrunner Gear & Maintenance 3 04-25-2007 04:16 AM
Hard starting Yammar 2GM KenD Gear & Maintenance 3 12-20-2006 04:15 PM
Hard Warm Starting Yanmar ysm8 mhfowle Gear & Maintenance 7 12-20-2006 01:45 PM

All times are GMT -4. The time now is 01:24 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.