How to do a Yanmar 2GM20F Engine service

We completed an engine service on a Y2GM20F engine in a 2002 Hunter 326 sailboat using the Niemiec Marine Y2GM20F Minor kit. We replaced the impeller, belts, air filter, and fuel filter. Filmed on location in Oriental, NC.
A list of all parts used:
Primary Fuel Filter
Primary Fuel Filter Bleed Screw
Impeller
Impeller gasket
Impeller belt
Alternator belt
Air filter
Coolant treatment
Marine Diesel Fuel Treatment
Engine kit used: 2GM20FE Minor KitPART #YAN2GM20FE Minor Kit
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[@liamstriker1211]

I would add that the shop manual says the air filter is to be washed in soapy water, and air dried. Only replace if it’s degraded. And folks, carry extra belts for sure. If either breaks you engine overheats. Then you overheat in 5 minutes. Then you blow a radiator hose. And of course belts only break while underway. So. If you overheat, anchor immediately and check your belts and raw water strainer for flow. Then impeller. Then seatow This and your filter change video are excellent.

[@MarkCartret]

Excellent performance and easy to see and understand. Thanks for this! It will save me $1000.

[@mskogly]

So nice and clean!

[@rock-climber]

Besides, I'd strongly recommend to replace the air silencer with an automobile zero-resistance air filter and to install a large automobile diesel oil filter before the low-pressure fuel pump. Then checking and replacing of this small red fuel filtering element will simply become unnecessary. There is always some dust and/or fine particles in the air inside the boat, so the good automobile filter will extend the motor's lifetime.

[@DougTreff]

Only thing I would do differently is to put down some absorbent pads to catch the excess fuel that drains from your filter. I use puppy training pads. They have a plastic backing and an absorbent pad. Easy to fold up and remove without spilling a drop. Less cleanup later! Really should do another video explaining the bleeding process. This is where most people have problems.

[@Unwrittentimeline]

Good point with the pads. I actually use them, but I pulled it up for the service and wipe it up after. I go over the bleeding process here kzbin.info/www/bejne/mXjSeqCLe62ep7sm33s Hopefully it will helps someone. Bleeding is always the irritating part without a good pump to push the fuel through. Thanks for watching.

[@gwendolynpitts5462]

Thank you for posting. I'm helping my dad work on his Hunter, and I wish I had seen your video a few days and one smashed thumb ago...we mistook the alternator for the raw water pump. I will be using what I learned from your video to do more maintenance.

[@Unwrittentimeline]

Glad it helped. Thanks for watching.

[@rock-climber]

Hey, the pump impeller is being installed wrongly. The Manual INSISTS on installing it while rotating the pulley CLOCKWISE to position the blades correctly. Here I see the blades being bended in the opposite direction. Of course, then the blades will self-position themselves, however while doing that they'll overbend causing the cracks.

[@maluhiasurfer]

Can I use a freshwater Yanmar 2GM20F in salt water? BTW great video!!

[@Unwrittentimeline]

I'm guessing you're moving your boat from a freshwater lake to the ocean. Congratulations on the adventure. Yes, you can operate the 2GM20F in a saltwater environment. Thanks for watching.

[@sockmon1]

Great video. Audio, video and presentation all well done!

[@unwrittentimeline2078]

Thanks for the compliment and thanks for watching.

[@dmaher2007]

direct and very easy to follow video, Cheers.

[@Unwrittentimeline]

Thanks, glad you enjoyed it.

[@rbbach1945]

Excellen video,great explanation.Thanks for taking time and trouble. Gratefully. Rick/Seattle

[@Unwrittentimeline]

Thanks for watching. Glad it helped.

[@Unwrittentimeline]

Hey Rick from Seattle! Thank you for watching! We really appreciate you and your feedback.

[@AndyKopac]

Might want to check your raw water anode. Supposed to check e wry 500 I think. On the block to right of lift pump.

[@benjaminchong82]

thank you so much

[@Unwrittentimeline]

Glad you enjoyed it. Hope it helps.

[@SailingPauHana]

Great video. Very thorough lesson.

[@Unwrittentimeline]

+Sailing SV Pau Hana (SV Pau Hana) Thanks for the compliment. Look forward to seeing you get your mast up and getting out on the water.

[@SailingPauHana]

You're welcome, and thank you.

[@barrywiles9831]

you forgot to show the important part that is bleeding

[@6663000]

The belts, impeller, and filters all looked fine to me... but I suppose unnecessary maintenance is better than neglect. Made for a good video at least :)

[@Unwrittentimeline]

Burial I could see the belts we're good before I started but wasn't sure about the impeller. Once you crack it open you might as well change it. I wanted to get it all to baseline. You never know what you have with a "new to you" boat until you open it up.

[@6663000]

You're right, with a "new to you" boat I would agree that it's good to set your own baseline.

[@erkful]

Preveventative maintenance...it’s a good thing.

[@pauleenwardbrown]

Have you made a video on winterizing the Yanmar 2GM20F Engine? It's our first time with our new boat. Also, you mentioned the primary fuel filter but didn't show it. What is the part number please? Thank you for your help

[@Unwrittentimeline]

Thanks for watching. Fortunately I haven't had to winterize yet. I keep it in warmer water when not aboard. If you do winterize, you want to drain all the seawater from the system with the petcock valves. Once the seawater is out you can either suck all the air out or fill the system with environmentally friendly anti freeze. You don't want to use regular antifreeze since this is going into the seawater system it may go into the water when you recommission next spring. I'm sorry I dont have a part number for the primary (non engine mounted) fuel filter. This is because there are many makes and models of these filters that can be used. It is not a standard set by Yanmar. If the markings in your filter have been worn off you can take a picture and ask a chandlery to help you find the right one. They should be able to recognize what type you need from the make and model of the fuel filter housing. I'm sorry I don't have better answers for you.

[@davidtilley2168]

This video doesn't mention replacing the engine anodes which I would think is crucial

[@Unwrittentimeline]

Thank you for the comment. While replacing anodes on an engine that has them is crucial, its not as big of a concern since this model doesn't have them. You are correct though. I should have mentioned it for our viewers with those model numbers. Thanks for watching.

[@annlisbethpedersen2140]

great video, very usefull, thank you very much

[@Unwrittentimeline]

+Ann Lisbeth Pedersen Thank you. Glad you enjoyed it.

[@petermclachlan5464]

Good video. Can you show how to bleed the air out of the fuel lines after changing the fuel filter on the 2GM?

[@Unwrittentimeline]

Glad you enjoyed it. Unfortunately I won't be on my boat for a couple weeks as I'm traveling for work. I do want to do a fuel bleeding video soon and will post it when I replace the filters again this fall/winter. Since I can't do it quickly you can check out this one from BoatUS kzbin.info/www/bejne/bJSzg4mwfr13mK8 I changed both filters. I filled each bowl with fuel so I wouldn't have to manually pump fuel into each bowl. It will save you a few pumps. Then you can either manually pump the fuel pump or pull the compression levers and turn over the engine. If you turn the engine be sure to close the raw water intake or you could hydrolock the engine. Pump fuel until fuel streams out of the vent screw with no bubbles and work your way to the fuel injectors if you replaced both filters. If you only replace the primary filter you can bleed the system to the engine mounted filter and that will probably suffice. If it is still hard to start or stops after a few minutes you'll need to bleed the system all the way to the injectors. Hope this helps.

[@briangilliland3620]

That was very good - thanks. Was it not necessary to bleed the fuel after the filter change or did I miss something?

[@Unwrittentimeline]

Glad you liked it. Hope it helps.

[@10000rajaram]

Great vid, I just bought a boat with a Yanmar Engine and am going to change the fuel filters. Do you know if the primer fuel pump on the engine can work to bleed to fuelsystem of air if both filters are changed ? Thanks =)

[@Unwrittentimeline]

Yes the fuel pump can pump fuel through both filters as you bleed the system. It will just take awhile.

[@10000rajaram]

@@Unwrittentimeline Great thanks, do i need to open the fuel injectors and bleed through that also ?

[@Swizzenator]

Missed the coolant . Thats what I came here for. Guess it doesnt happen too often so the reason I'm guessing its not general.

[@Unwrittentimeline]

Mike, Sorry for not having what you're looking for. The coolant itself isn't very often. When I serviced this engine I did test the coolant with a coolant tester amzn.to/2GTapfk I found it to be within the required temperatures or I would have replaced it in this video. In case you're looking for something more like the heat exchanger service, I did complete that and it's scheduled to be posted 23 June. I used a product called barnacle buster amzn.to/2IMLZ3n to descale and clean the seawater side of the coolant system. I rinsed it out and that's really the gist of it. I used an extra bilge pump to push the cleaner and fresh water through the system. I hope this helped a little. If you are still looking for the heat exchanger video be sure to subscribe so you don't miss it, or check back in June. Thanks for watching.

[@dennispittis1960]

Gear box fluid how much

[@barrythomson5232]

Great vid, thanks for this. What tooklit do you require for this?

[@Unwrittentimeline]

Thanks for watching. No special tools were required. You'll need a flat and Phillips head screwdriver, a couple wrenches for the impeller and alternator belts and a bar to maintain tension. If you do the oil or fuel filters you may need an oil filter wrench or strap wrench.

[@barrythomson5232]

@@Unwrittentimeline Hey - thanks for your reply, that's great!

[@Heros4gold]

What kind of oil pump is that? where did you get it?

[@jaf6969]

Any ideas what to do if you need to remove the front of the heat exchanger but have rigid pipes on the "IN" and "OUT" of the fuel filter.....am I going to create havoc if I remove these from the filter so I can remove the plate that allows front access to the heat exchanger?! thanks in advance...by the way - excellent video...:)

[@Unwrittentimeline]

Thanks for the compliment. It shouldn't be a problem if you have hard lines to/from the fuel filter. You can disconnect them with the banjo bolts, unbolt the filter and get to the heat exchanger. The lines will stay generally in place but you should be able to maneuver the exchanger out. Remember to shut off the fuel before you begin. You'll need to bleed the fuel system again if you disconnect the lines. Maybe some new flexible line is in order to save the heartache next time you just need to service the heat exchanger.

[@jwrcolombia]

I also am confused on looking for the right pump. I saw your video on replacing the Impeller pump. But where do you find the pump that controls your coolant/antifreeze? I am having a dickens of a time trying to find that part.

[@Unwrittentimeline]

I haven't actually replaced the coolant water pump yet. I only replaced the sea water pump that contains the impeller. I would order mine from Niemec marine, but if they won't deliver to you try to find a Yanmar dealer near you. It doesn't have to be a diesel Yanmar dealer. Any shop with Yanmar engines should be able to order it or at least point you in the right direction. We have several boat yards near Oriental that can order parts as well. Hopefully someone near you can help if you can't get it delivered.

[@jaybeez99]

I'm sure Iannuzzi could have done it for you.

[@bobmorris5325]

My engine is over heating. Is there a thermostat? How often should the heat exchanger be cleaned?

[@Unwrittentimeline]

Bob Morris Too bad about your overheating. The thermostat on the 2GM is located to the left of the alternator. You can pull it and put it on a pot of water to test it. It should start opening at 42C and be fully open at 52C. The manual recommends changing it every year or 2000 hours. You can clean the heat exchanger by using a Barnacle Buster type of acid and running it through the system or you can remove the caps and descale it manually. You may want to do both. First run Barnacle Buster and open it up to ensure it's all clean. Sometimes if you've had an impeller desintegrate you can have pieces of it blocking the path to he heat exchanger and they need to be removed by hand. Hope it helps.

[@bobmorris5325]

Thanks for your quick reply. I will look into both of those items this weekend. Great video BTW.

[@jwrcolombia]

Also the book that came with the engine has 3GMF written on the book even though the actual lettering says 2gmf20 and several others. The placard on the engine says 3GMF but the engine is 20HP and 3200RPM. I am confused. Looks like Coolant is leaking and spraying, may be a hose or the coolant pump. But it looks like any pump I have found is just impeller seawater pumps! I am lost!

[@Unwrittentimeline]

It sounds like you're having quite a problem. Hopefully I can help. Your engine has a data plate that lists the engine type, 2GM/3GM and the engine number. This looks like a silver plate with a green bowtie on it. It is located just to the left of the water pump on the 2GM models. This is the engine you have regardless of what manual came with your boat. Many of the manuals have 3GM on them with sections on the differences between the engines in the same manual. Be sure you're looking at the schematics for your engine. You can give the guys at Niemec Marine your engine number from the data plate and they can get you the correct parts. They do sell the coolant pumps as well. If that is where your leak is coming from you can replace or rebuild the pump. Without seeing it I can't tell you where the leak would be coming from. Hopefully you can track it down and figure out where your problem is. Tracking down a leak can be hard, but if it's spraying out you should be able to find it and replace the pump or hose that is leaking.

[@johnrogerwood5114]

Do you know what the raw water (aka sea water) cooling water flow rate (gpm) is suppose to be for this engine?

[@Unwrittentimeline]

Thanks for watching. Excellent question. I'm sorry but you've stumped me. I looked in the manuals I have for the engine and cannot find a reference to the raw water supply pump gpm. I only found the psi (13) for the freshwater (coolant) side. It may be something that isn't published due to a variation of requirements based on engine rpm. The pump turns faster with faster engine rpm. Perhaps an email to a pump manufacturer or Yanmar might give you a better answer. I wish I could have helped more.

[@johnrogerwood5114]

Just from Sailboat Owners Forum - 700l/hr @ 2720rpm engine speed. From page 7/8 of Yanmar Service Manual.

[@Unwrittentimeline]

Thanks for finding that out. I see that now.

[@jwrcolombia]

Where did you get the kit from? A reseller?

[@Unwrittentimeline]

I got the parts kit from Niemiec Marine marinedieselparts.com/store/2gm20f_yeu.htm I ordered the oil pump from Amazon. amzn.to/2jyt4zu Links are in the description as well. Thanks for watching.

[@jwrcolombia]

found the link...disregard.

[@MrBluoct]

thanks parts link not working. ..

[@Unwrittentimeline]

Thank you for letting me know about the link. I re-copied it and it should be working now. It is marinedieselparts.com/store/2gm20f_yeu.htm In case it gets broken again. Thanks again, hope the video helps a little.

[@MegaAstroglide]

Good information but the editor continues to cut off what he is saying in every episode. This is rather annoying and leaves me hanging as to what he was going to say.

[@MegaAstroglide]

Please disregard this comment as I meant this for another video. Thumbs up for this guy. I apologize for confusion.

[@antoniolim3567]

tenawaran m ng 290k dalawa bibilhin problima d kami nakabalik nag kaSakit si manoy parang passbrk na sya sa amin kc nahawakan ng hallseller or bder muralang kuha nito sa philip morres baka nasa 200k la ini

[@SOLDOZER]

Impeller vanes should be straight, not curved. Yours are curved because it's worn. You dont know what you're talking about. That impeller was toast.

[@Unwrittentimeline]

Thank you for the comment. I'll pass all your well-articulated thoughts onto Yanmar so they can change their procedures based on your learned and wise assessment. Hopefully, other viewers will see your response as well. I'd like them to be aware of what the manual actually stipulates instead of what some guy who attempts to flame me on the internet says. I have multiple references to back up my video. You have only derogatory comments. When inspecting the impeller, the Operators Manual states "Impeller blades are cracked or nicked. Edges or surfaces of the blades are marred or scratched" No mention of bent blades. The shop manual states "Inspect the impeller (4, Figure 24) for cracked blades or excessive wear at the tips of the blades. Replace the impeller if any defects are noted". It also states, "The impeller only operates in a counterclockwise rotation (viewed from the cover side of pump) and remains in a flexed (compressed) position at all times. Over time, this causes the impeller to take a set in one direction." At no point in any of the literature does it say curved blades require replacement. The manual actually references curved (set) blades but does not list this as a defect that requires replacement. This has also been verbally confirmed by Yanmar dealers. I inspected the impeller in accordance with the Service Manual, Shop Manual, and Operators Manual. I think I'll stick to those references.

[@harryweyer2174]

Your full of shit,the new one was exactly the same,if your not part or the cure your part of the problem.take care.

[@harryweyer2174]

UnwrittenTimeline what I did notice you say tho is that the cooling system is salt water,I was under the impression that only the exhaust used salt water for cooling and the engine was freshwater coolant.cheers.

[@Unwrittentimeline]

@@harryweyer2174 I apologize if I didn't say that correctly. You're right marine engines use saltwater to cool the coolant through a heat exchanger much the way a air cools the coolant through a radiator on a car. Then the water is also usually mixed with the exhaust to cool the exhaust gasses prior to exiting the vessel. Thanks for letting me know. I'll try to mention that in future videos.

[@harryweyer2174]

UnwrittenTimeline not a problem at all,take care.