Yanmar 2gm20f

[jeremy34]

I am having some issues with my Yanmar engine and was wondering what everyones thought was. Two problems really. First I was out a couple months ago and motored the engine for about an hour at cruise then pulled back to idle to get into a slip and the buzzer started chirping at me no lights come on just a chirp here and there. Thought maybe an oil pressure deal and figure since I was at idle maybe it was just on the verge of being low. Then yesterday I was out had the motor running about 2600 rpm up river for about 1.5 hours and the thing started the chirp thing again but this time at high power settings. I was 20 minutes from my destination so kept running it. Bumped the rpm up to 2800 and the chirping stopped. then started again. came up to the dock and slower it down and it continued to intermittently chirp. Never seen this when just running my usual 20 minutes in and out of my slip.

The other problem I am having is when starting a cold engine it has to crank a little bit and then tries to run on one cylinder for a few seconds before the other one finally come on. after it fires up it seems to run fine and restarts are no problem. Seems to be more noticeable on extra cold days or after sitting a couple weeks. (it is summer so extra cold is like 50f as oppose to 80 but not sure that there really is a difference)

I really don't know much about diesel engines and am considering having a mechanic come look at it but am afraid at what that well cost. There is a yanmar dealer a cross the street should I go with them or a yard.

Any advise would be great.

Thanks

 

[Steve Dion]

Birds can cause chirping!

Check out the sensors for your water temp and oil. My water temp sensor was loose on the sending unit and I had the same type of intermitent problem.

When I shut my engine down I let it idle for about 5 min. then I rev it up to about 2,000 RPM and pull the fuel shut off. This is supposed to remove any excess fuel from the cylinders.

I am guessing you may have a leak and that one cylinder may not have fuel at the injector when you are firing it up. I would check and/all of those copper compression washers (just replace them) and check the other washers for any damage. Also have your injectors checked too.

Try advancing the throttle a little when you start your engine and see if that makes any difference. Some engines need more advance than others.

 

[navigator97]

Relative to the second problem, it may be a dirty or worn fuel injector on one of the cylinders.

 

[Benny17441]

Assuming the warning lamps are operational and since you indicate no lights went on went the buzzer was chirping I would be inclined to say your sensors as well as your systems are OK. The fact that the buzzer is chirping injdicates the presence of an intermitent electrical short. Don't know if your boat is of the Cherubini series (74-83) or the newer models (88-94). The wiring harness that goes from the engine to the control panel is fed through some sharp fiberglass corners and specially in the older boats with years of hull flexing some of the insulation gets chaffed causing shorts. One characteristic of this ocurrence is that the shorts become worse and more frequent with time. Get your head down below the cockpit sole and inspect the harness specially at the bends and if you see the black cover is broken check the insulation of the wires inside. You may also test for a short with a continuity tester. This may not turn out to be the problem but in the older boats it sure sounds like it. I pressume that when you shut the engine down the oil pressure light will turn on and the buzzer wiill sound loudly. Regarding the engine it sure sounds like an air leak to one of the injectors. For us here in Florida water temperatures in the 50s is very cold. The oil gets thicker and the engine cranks slower. That could be the reason why your engine firing problem may be more noticeable in cold weather.

 

[jeremy34]

Thanks for all the advise this is my second post and am amazed at how fast I get a reply. A few answers to remarks. It is a 1990. The lights light up when engine is off and key on along with the very loud buzzer. I do advance the throttle maybe half way to get it to start that's about the only way as it seems the one cylinder needs the extra throttle to run until the other cylinder finally starts then I quickly pull it back.

Remember I am a newbie at this. Once I pull the injectors out should I take them to the yanmar dealer to have them flow tested or do you just clean them with something and put them back in.

As for the chirping I hope it's not a shorted wire that can be a pain to find. I find it odd that the only 2 times I have heard it out of the last 20 outings were the only 2 times the engine ran for 1+ hours.

Well not sure when I will get out to the boat to look at it but will post back with what I find

 

[Warren Milberg]

Start with the easiest things first. Are your oil and coolant levels full? Are all wiring harness connections bright and tight? Are the connections to all your engine sensors secure? Are all the crimps on your main switch tight (I had two out of three loose and they were factory crimps)? Are any of the bleed screws on the primary/secondary fuel filters and injection pump loose? Are the high pressure connections to the fuel injectors tight? Any obvious fuel leaks anywhere in the engine compartment?

 

[sailaway78]

Ideas on both

As for your buzzer chirping, look for a short to ground. The switches just go to ground to make the lights and buzzer go off. Personally I prefer real guages, and have installed both oil and temp. As for the harder starting. I had a 2QM in previous boat, and when the temp got below 50 or so, it would take a little cranking time, and starting was best at full throttle. For yours since it runs on one cylinder for a few seconds, I think I would first check everything for a slight leak, allowing a little air into the system. These can be a real PITA to locate, but a good starting place is the banjo bolt on the intake side of the lift pump, and the gaskets on the filters.