View Full Version : 2gm20f precombustion chamber

06-15-2008, 10:48 AM
"I have the head off. The precombustion chamber will not just slip out of injector hole. There are carbon deposits.

How do I "dissolve" or otherwise remove carbon to get the chamber out? Is it safe to tap the chamber "nose" that sticks out of the head between the valves, maybe with a piece of wood?

The exploded drawing of the injector in my Clymer manual (Fig. 23) shows a "gasket" and "heat shield." I have a new yanmar part called an "insulator", but it does not look like the "heat shield", which in the head has a copper wafer top. Is the copper wafer top, the "gasket?" If so, I do not have that part and any recommendations about where to get it will be much appreciated.



http://www.marineengine.com/discus/messages/12498/171721.jpgyanmar precomb chamber

06-21-2008, 11:06 PM
"You can see part of the insulator that is the second layer, it is a graphite substance. Over that is the copper waffer Then your Fuel injector. Dig out the insulater and fit te new one on the precup shoulder. Clean with a rad and doweling. To knock out the insulator A & B we use a socket that fits close to the dia of the precup and give it a good "rap" with a good hammer. It will come free. There are also copper washers that go between the precup & hean and between the second par of the precup. The precup is a 2 piece assembly. Head off? You may as well service the valves.."

06-23-2008, 12:57 PM
"Great answer! Many thanks. For future reference I am posting two pictures of the precombustion chamber (both pieces) and the "wafer" you refer to that came out with the chamber. Note also the graphite "washer" groove in the "top" of the chamber. I have found these parts at Blue Water Ships Store in Corpus Christi, TX, a great bunch to deal with.http://www.marineengine.com/discus/messages/12498/191421.jpg2gm20f Precombustion chamber

06-23-2008, 01:00 PM
"Here is the other picturehttp://www.marineengine.com/discus/messages/12498/191425.jpgPrecomb 2

06-24-2008, 06:25 AM
"hey everybody
I have yanmar (3TE) inboard eng, and i need thermometer.
where can I find it?
it's too old"

06-24-2008, 08:24 PM
"I am not familur with this model, is it fresh water cooled or raw water cooled. What kind of thermometer is used now? give me a make and or brand. Also what range is the meter face?
Also what does this engine run? Power or sail boat or is it auxillary power./"

06-25-2008, 02:35 AM
"hi ron
hope you fine,
it's raw water cooled and it's fixed on my sail boat.
I'll try to show you the picture later.
I'm from Bahrain