[Public-List] Diesel Help

[brooks.glenn at comcast.net]

Hi Jonathan, 


I am not an expert, by any means, but you might want to get another opinion from a second mechanic. The mechanic's compression loss suggestion doesnt seem all that valid. Most engines with a decompression system will drop compression for hand cranking at least as much as what your compression loss test shows, if not more... 


Do you have glow plugs in the engine? Diesels designed with glow plugs typically need these to start. The glow plugs in each cylinder are needed to preheat the air in the cylinder prior to starting. Makes a better environment to fire off the fuel air mixture during each compression stroke. My universal marine diesel has glow plugs, to which I inadvertently disconnected the wiring harness during a winter layup a few years ago, and could not get the engine to start the next spring, without extended cranking. It would turn over forever, pop fire and stall, then blow diesel smoke out the exhaust, eventually after extended cranking - like 30 - 45 seconds or more, would start, and restart right away when hot... Which sounds a lot like your symptoms. In a flash of inspiration, half way through the season I traced the glow plug wiring and found it disconnected at the engine. Once I plugged it back in, everything has worked fine. 


BTW, in the big commercial diesels, a small spurt of water in the fuel will blow out the glow plug elements in one or more cylinders, and cause the same starting problem - so there could be two things to check - harness voltage going to the plug (most likely) , and the little sparky "anodes' in the plug end. 


Cheers 
Glenn brooks 
Dolce 319 
----- Original Message ----- 
From: "Jonathan Adams" <laughing_gull at verizon.net> 
To: public-list at alberg30.org, "Alberg 30 Member List" <member-list at lists.alberg30.org> 
Sent: Monday, April 11, 2011 10:19:51 AM 
Subject: [Public-List] Diesel Help 

Well I finally have a question that I really need an answer to - versus one 
where I am looking for an opinion! 

I have a Yanmar 2GMF. It is between 20 and 25 years old, and for the last couple 
of years has been having a hard time starting - I might have to crank the engine 
for a number of extended periods - minutes. This spring, I had Bayshore Marine 
look at the engine, and they checked injectors and performed a compression test. 
The injectors are fine, and the engine once started runs well. If it is warm, it 
starts immediately no problem. Once running, it can hit its top revs (~4k+) 
under no load - which indicates that the fuel pump / timing is good. 

The result of this visit - other than lightening my wallet - was that the lack 
of compression was creating the problem. It is meant to be 469lbs and is 400 in 
#1 and 415 in #2. The only way to deal with this is to check either the head or 
the piston rings. Either way it is an expensive proposition. can I get it to 
last the season? It is only a matter of time before I burn out the starter motor 
and / or drain my batteries. 

The mechanic recommended: 

1. release the compression on the cylinders, and crank the engine to warm things 
up, and then start 

2. While doing this close the water intake valve, as the muffler has no exhaust 
to speak of when you are cranking and will fill up with water which could back 
into the engine. 

3. He recommended putting CRC into the air intake to help seal the pistons. He 
did not recommend starting fluids as these damaged seals. Someone else has 
recommended putting in heavier oil. 

Any advice from the crowd? If I send the engine to Bayshore, I essentially get a 
new engine, as they will warrenty it, and totally overhaul it while it is out. 
However, this is sure to seriously impact the boat fund. Any recommendations for 
a good mechanic that is not a crack head? The reason I went back to Bayshore was 
I kept running into crack head mechanics. 

Jonathan 
197 
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