Overheating - Troubleshooting a small diesel sailboat engine - a Yanmar 2GM20F

After steam started coming out of the exhaust, followed by a high temp engine alarm, It's time to start troubleshooting the raw water side of a Yanmar 2GM20F engine. I take a look at the raw water strainer, raw water pump, heat exhanger, antisiphon valve, and the exhaust mixing elbow. I don't think the problem was just one thing, but a few things compounded together. One of the splines was missing on the impellor, another was cracked, and the heat exchanger was heavily scaled and partially blocked. See more detail in our blog. diysailor.com

[@creigmacc]

I'm amazed how boat owners will change the oil at half the hours recommended by the manufacture. Yet hardly ever consider the cooling system/heat exchangers. Way more broken motors from overheating than dirty oil out there. Thanks for taking the time to produce the vid.

[@mattdouglas5570]

Very helpful and possibly the best video I've found on this subject

[@michaelinkster4977]

Slight engine overheat combined with steam/white smoke on Volvo Penta 285 hp: impeller OK, cleaned the heat exchanger, checked exhaust elbow, checked raw water flow and all seemingly OK. The six injectors were all removed and sent away for testing and they were all clogged and varnished up. The tips were replaced and they were thoroughly cleaned and soaked. The service shop said that there was a poor spray pattern and most likely unburnt fuel causing heat build up etc in exhaust and thus steam and smoke. Re-test due soon but hopefully that will be the end of the problem!

[@okcpicker]

Thanks again Orange Fish. You do a great job describing/showing everything. Please produce a video on bleeding air out of the fuel system. Thanks

[@Korbin57]

To get rid of mineral deposits I use white vinegar. Cleans my coolant system overnight while I sleep. To keep the hoses from sticking to the metal piping I use Permatex Aviation Gasket sealer. Works great.

[@77sailordude]

Heating the hose with a heat blower helps when removing it. Good informative video 👍

[@steadmanuhlich6734]

Good demo video. Good narration. Good description of tools and tips.

[@Richdudevids]

it took me some time to find a sail boat video that useful tip and dyi stuff thanks for posting

[@Ingeanous]

Thanks for the comment and the best of luck with your DIY jobs.

[@andreruegg9490]

Great video, Thanks for sharing. I'm feeling more confident to do this myself now.

[@gsallen9588]

Very smart usage of hand tools and chemicals on that kitchen engine. Bravo!

[@tunamaniak]

Hi Orange Fish great video, A few tips if you don't mind for next time. 1) Do this annual before you launch the boat and replace the impeller and save the old one. 2) I always remove exhaust elbow 1st and plug the exhaust with a rag or plastic bag to avoid any moisture to enter the exhaust system. Now you can clean the exhaust elbow on the inside and inspect for corrosion. Corrosion starts from the inside. 3) I simply pull out the heat exchanger and soak it overnight in vinegar 1 US gallon and rinsing it the next morning. After a good rinse I can see witch tubes need a tune up with a pipe brush. 4) Clean all the O-rings and treat with vaseline and I use dialectic compound on threads and nuts. 5) After seeing you use the de-scaling solutions I look forward to try that myself as a half season solution. Nice boat

[@Ingeanous]

Good tips! The impeller wasn't that old, but since the heat exchanger was partially closed, it might have contributed to its early demise!

[@davidbradley3074]

get a spray can of molybdenum disulfide and place your fasteners in a can, while shaking the can spray the moly into the can for about 10 seconds. This will coat the fasteners threads well and then re-assemble your parts. Moly is a dry lubricant and so next time when you have to work of you heat exchanger you will not have to worry about stripping threads or breaking a bolt. also, first take a wire brush and brush all bolt / nut threats until clean before coating with moly.

[@bigredc222]

A friend gave me a qt. can of powdered molybdenum, I'm always trying to find uses for it, I use it for sliding surfaces like drawer slides, but I never thought to coat bolts with it, I'll have to remember to do that, thanks.

[@chuckdenicolo5164]

I plan on doing this, so thank you for posting this video!

[@WESTOFEDEN71]

Very helpful. Excellent delivery. My boat and ya at is 46 years old and was potently neglected. So, it helped to freak me out too even tho I am a killed diesel mechanic the marine portion is new to my. Seems I have some work ahead.

[@MrHradecky]

Got to share my experiences. We are in between boats now, but our last boat was a Hunter Vision 36 with a Yanmar 3JH2E engine. I cleaned my exhaust elbow twice and the heat exchanger once. Did it myself, no radiator shop. Very simple, I took the parts off, removed their gaskets and boiled them out in muriatic acid in a 5 gallon bucket. Soaked them for less than and hour and they came out looking like jewelry. Neutralized in a soak of ammonia and they were good to go. Put them all back together with new gaskets and she ran cool as a cucumber. It's amazing what sealife grows inside those parts. And the carbon build up. I found a lot of confetti plugging up my exchanger, presumably from 4th of july celebrations we attended in the delta.

[@shanek6582]

Keep ammonia away from brass or copper, does some bad things, neutralize with baking soda.

[@sailingvesselsouthernlady447]

Thanks. That was a really good "how to" video. It's time I clean my Yanmar as well

[@Ingeanous]

Thank you for the positive feedback. An unexpected outcome from cleaning out the cooling system was the engine ran with less vibration. I'm guessing it's since less energy was expended on pushing water through the cooling system.

[@brucemacsr.6776]

Orange Fish great.

[@cobrasvt347]

I just realized how exacy similar your yanmar diesel is to my ym 1500d tractor. That's awesome and if it's as reliable and bulletproof as the tractor engine has been with an extremely high amount of well maintained hours that I have on her, you will have no issues with it as long as the maintenance is done and she keeps cool it will rum forever. 🖒

[@captlarry-3525]

routine maintenance beats alarming failures every time

[@fredbrillo1849]

Consider yourself so lucky to be able to access the rear of your engine.... Ive got a Watkins 29 and have to get into the lazarette and reach in through a small hatch to get to my exhaust mixing elbow and my shaft stuffing box. Not fun on a hot summer day in South Florida.

[@Ingeanous]

Concur, with our old US30 sailboat, I had to snake myself into one of the cockpit lazarettes, and lay across tanks and such to even see the back of the engine. It originally had a Volvo MD7a, and we eventually repowered with a Beta 16, but rear access didn't get any easier... The worst job ever was replacing the stuffing box. Yes, she was out of the water, but it was still a crazy cramped job... I am 6"2"

[@ecmunpublished]

Thanks for the video, very helpful.

[@ken2633]

I grease the hose with anti-seize so it's easy to separate from the exhaust. Greased the gasket with anti-seize as well, never have to change gasket for years as it won't stick to metal nor gets damaged.

[@mainer1755]

i seldom post, but thank you. I have the same engine in an old Bristol 32. Cools just fine, but clearly I'll need to do this some day. Your video is a big help.

[@Ingeanous]

Thank your for the comment! Fair winds and following seas!

[@ryanbousquet3533]

Hargrave, I am not sure where you are located but I also have a Bristol 32, that unfortunately has seen the end of her life. That being said I have a lot of things from her that you may be interested in and I would love to pass on to a fellow Bristol 32 owner. Contact me at [e-mail] if interested.-Ryan

[@CessnaPilot99]

Ryan Bousquet Did Hargrave ever contact you to get those things you were going to give him?

[@leiferiksson2248]

Thanks ! Great video, really helpful.

[@lorenwilson8128]

Nice to see a DIY job like this. You can buy a stainless steel or brass cylindrical brush from McMaster online, among many places. Just like a bottle brush or test tube brush, and perfect for cleaning the heat exchanger tubes.

[@Ingeanous]

Just wondering, would you think a brass or stainless brush would be better?

[@lorenwilson8128]

Depends on the material you are scrubbing. If the tubing is brass, copper, or aluminum, use the softer brass brush.

[@PatrickFranzCA]

Thank you, thank you, thank you for posting this!! It looks like mine is completely blocked (water gets to the exchanger, but not past). You just saved me a a bunch of $$ and a argument with the wife!

[@Ingeanous]

Awesome ,and good luck with your DIY adventures! It's fulfilling to accomplishment fixes that your were be able to troubleshoot, and solve without calling in help. Good times to look back on someday, and maybe help out a fellow sailor. And great following seas to you....

[@shanek6582]

Measure the ID of the tubes and get a copper bore brush for a pistol, whatever caliber is close.

[@jeromewelch7409]

White salad vinegar 8% acidity Walmart very cheap per gallon great the scaler..... Nice vid....

[@davidbradley3074]

ABSOLUTLEY! Let it sit submerged overnight in a a plastic bowl.

[@rickyrodriguez5744]

A very informative video. 👍🏿

[@davidamar4687]

The best informative video. Thank you so much

[@Royden58]

Use a wood dowel to clean the internals of the tube nest

[@stanthology]

To keep hoses from collapsing, buy a stainless steel spring , the same diameter as the inside of your hose. Made for that purpose. Available from automotive parts stores. Cheap insurance to prevent overheating. Blown head gaskets,all that good stuff

[@legeantdavid1937]

Thanks for the video I’m going to do this on my kubota 50

[@Ingeanous]

We repowered our old boat with a Beta 16, which was a Kubota based engine. Similar to the Yanmar, but different. We never had any problems with the Beta! Of course we did the regular maintenance and she reciprocated by always good to us.

[@SvMobyduck]

Thanks for the video, it looks like you were using a kobalt socket set which is my favorite however when breaking bolts it is unwise to use their 12 point deep sockets on a six point bolt. A 6 point socket is worth it's weight in gold that will only prove it's value when that extractor doesn't work. I pass that to you having already paid some very costly prices. Also a good swivel is good for the wrist somtimes

[@Ingeanous]

Fixing boats in exotic places is what I've read, you've got to use what you have available. I'll have to Goolgle you suggestion and maybe add it to the wish list. Thanks!

[@otm646]

Using a lubricant like that on the threads, or ever worse under the head of the bolt is a recipe for over tightened fasteners and stripped threads. I understand you're trying to prevent corrosion, using a zinc rich anti seize. The zinc is sacrificial and protects significantly better than a barrier coating like the Lanocote.

[@Ingeanous]

Thank you for the feedback, will keep that in mind next time!

[@cobrasvt347]

Always use 6 point sockets. You will never have to deal with a stripped bolt head ever again. 😉

[@waynep343]

speedometer cable core. steel cable can also be used but its much stiffer than speedo cable core. . it can be really handy to clean out bent tubing and other tubular devices.. and you really should invest in some ball end extensions for your socket set.. so much nicer to use.

[@yachticus]

I would argue on the barnacle buster - we have trialled a few and a US Product Rydlyme - nothing short of brilliant - MILSPEC and "good"for the enviroment

[@timlamarre8680]

thank you!

[@weburnitatbothends]

Beercan island? Sounds like a great place

[@hommie789]

When you got the overheat light and alarm did you check your discharge to see if water was flowing through the system or did you just assume it was a plugged heat exchange? Did you check the inlet strainer? Or the through hull fitting to see if it was building up with barnacles? Great video but missing a few details for other do it yourselfers.

[@Ingeanous]

@Paul Schuster Close the raw water seacock to the engine, open up the top of the strainer. Have some start the engine and pour the descailer in at the rate the water gets sucked down in the strainer housing.

[@fredbrillo1849]

Welding Rod or a small caliber gun brush works great for reaming out the tubes.

[@Ingeanous]

A gun cleaning rod would make for a good cleaning tool for this job, just something I did not have on hand at the time.

[@andersjakobsen9906]

I`m going to bye a Cat whit TO of this engens, so i realy like your videos :-) Big thanks! Impeller I know how to change ;-)

[@Ingeanous]

Cats are awesome... maybe someday. Anywho, the older Yanmars are easy to work on if your a little bit mechanically inclined. Good luck with your new boat!

[@andersjakobsen9906]

Yeh...I know my way a round. Grew up on my dads back ;-) But it was nice to see how the engien was. Too see were everything was located. The motors only had 280 h. and 293h So they should be good. But thanks again. Nice film clips.

[@yachticus]

we have found a more reliable way with the descaler - a 20 litre bucket and a small 12v pump - essentially get your solution I think its 50/50 and hook into the raw water supply pumping thorugh the completes cooling system with the recovery line that feeds the exhaust elbow being the end of the circuit - circulate in one direction for 20 mins - the swap the flow so you push in from the exhaust side and recover back to your 20 litre bucket from the raw water supply. Seriously effective. - I would really like to know what the tool was you used to take out the stripped nut

[@michaelpolunas6129]

Great video. Did you drain the coolant before removing the heat exchanger end caps or do the core o-rings maintain the seal. I need to search for missing impeller veins this weekend.

[@Ingeanous]

If the impeller veins haven't made it all the way through to the exhaust, I'd imagine they are stuck on the input side of the exchanger or in the cooling tubes.

[@allanbranch]

Have you seen anyone put a freshwater rinse option on their motor? Seems like an easy fix for a lot of issues and just cycle 60 seconds of freshwater after each usage to say frustration later.

[@Ingeanous]

I have, however, when the salt water is running across the hot exchanger, I'd imagine the scaling build up was done and a fresh water flush wouldn't remove it all.

[@dreadlysmellybum]

Invest in a good set of socket extensions.

[@sighpocket5]

Nice!!!!

[@hunterwdavis]

Enjoyed the video! What’s the name of the intro music btw?

[@Ed-ip2sg]

Doesn’t the heat exchanger slide out of the housing for thorough cleaning?

[@snakeplisken4278]

interesting. silly question, but where to introduce the de-scaler into the system?

[@Ingeanous]

Just closed the seacock and opened the top of the sea strainer and poured in the de-scaler to match the amount of water the engine was pulling in.

[@k1mgy]

Looks like lanocote is not recommended for high temperatures. Have you had any issues since using it?

[@diogoribeiro2815]

Great video my friend! Let me ask you, is not necessary to take out de mixing elbow to access the back of the heat exchanger, right?

[@Ingeanous]

Yes, the mixing elbow is considered a wear part that needs to be replaced. The stock cast iron ones will last for years, but supposidly the stainless ones will last forever becuse they don't corrode like the steel does in salt water.

[@chuckdenicolo5164]

I have read that the heat exchanger tube assembly will slide out so it can be taken to a radiator shop. Did you try pushing it out?

[@Ingeanous]

I did not, but looking from the top down with fill cap removed, from the fresh water cooling side, it looked very clean so I didn't go down that rabbit hole. Thanks for the reply Chuck.

[@chuckdenicolo5164]

Thank you! I feel much more comfortable taking on the same project with mine now.

[@MrHradecky]

Yes, it pushes out easily. Just soak it in muratic acid, then neutralize the acid by soaking it in ammonia.

[@milkoberben2963]

@@MrHradecky it does come out easily

[@bosmanlechu]

How many hours was this engine? Mine is about 2000, used in slightly salted sea (Baltic) and there is no troubleshooting with overheating. Is it time to inspection or not?

[@Ingeanous]

Unfortunately, our engine is older (1990s) and is not equipped with an hour meter. With that said, the cooling system will start to clog over time with salt and other organic buildups adhering to hot surfaces, so this is a good exercise in maintenance to keep the engine healthy regardless of the type of water lives in.

[@stuartcarduner5855]

Very helpful (but does anybody want to watch a full minute of your intro video every time?)

[@Ingeanous]

I agree with you, If I do any future vids I'll do an abbreviated intro... It was a thing at the time... Thanks for the feedback!

[@johnnybfromhousotn3900]

what marina do you have your boat in St Pete??

[@Ingeanous]

We were in St. Pete Municipal Marina, Dock 3 for a few years. She now sits in our back yard in Port Charlotte, FL.

[@chriscounts1646]

Hey Orange Fish, I live in Palm Harbor and just purchased a sail boat with the exact same engine. My question is you mentioned you went to your local Yanmar dealer and picked up some parts. Who is the dealer? I need to grab some parts for my cooling system as well and want to expedite the process. Thanks!

[@Ingeanous]

yachtpowerproducts.com 1510 1st Avenue North St. Petersburg, FL 33705

[@chriscounts1646]

Gracias

[@TOMVUTHEPIMP]

Could have ran some brass brushes used for cleaning gun barrels through the heat exchanger instead of jamming tools in it.

[@tracecological6816]

That cooler could have been descaled, it really needed it.

[@louissparks2496]

Did you check your intake?

[@Ingeanous]

yes

[@riphaven]

so this was your last video, did it work? did it stop overheating?

[@Ingeanous]

I've been busy with other projects. But to answer your question, I still have the boat, and that was the last time it overheated :)

[@riphaven]

cool, that was a great learning video, thank you for posting.

[@douglundy5755]

Job done? did we get another hard run to check for overheating?

[@Ingeanous]

Albeit 6 years later and with light use, have had no overheating coolent issues... probably time to do it again.

[@womackke]

Subscribed

[@mbiriviri]

One minute music video intro! Who in the world wants to watch a minute of pictures of you when they’ve come to learn about something????

[@jonathanbailey7311]

Where in St Pete do you get you parts. I'm tired of West (Theft) Marine prices. Here in Treasure Island.

[@seanlathbury5410]

BFS screwdriver. 😁👍

[@Ryuuken24]

Barnacle buster helps marine engines.

[@RATADATUAVELHA]

why didn't you flush it to a reservoir instead of flushing to the sea?

[@petersrightbut8297]

Where can I buy that B.F.S. screwdriver? Lol...

[@scdevon]

Nice work. I don't know why there aren't more air cooled small diesels in boats this size. Providing enough air cooling via an engine compartment exhaust blower seems minor compared to all of the other hassles with heat exchangers and raw water cooling accessories that the boating industry has to engineer into water cooled boat engines. Thru-hull fittings are responsible for sinking a lot of boats in one way or another, too.

[@johnnybarbar7435]

A blower is no where enough CFM's to keep the engine compartment from overheating. Even if you did have a huge blower ventilating the compartment, air cooled radiators do not do well in a salty marine environment.

[@scdevon]

Never heard of an "air cooled radiator" except maybe an intercooler for a turbocharger. A ducted fan blows air over cooling fins on an air cooled engine and that air has to be dealt with, that's all. We're talking about an engine that makes about as much heat as a riding lawnmower in a small sailboat. Deutz actually makes air cooled marine diesels (big) and there are KZbin videos of Europeans running smaller air cooled diesels in open fishing boats where air obviously isn't a problem.

[@MrHradecky]

The ventilation required would make the cabin uninhabitable.

[@MrBugsier5]

aircooled engines are mutch more noisier, and dont forget, the exhaust sistem. using raw water in a cooler, and clean cooling liquid in a boat engine is way less complicated as you think, aircooled is way oldfasion.

[@BillSikes.]

scdevon I agree, nothing but aggravation, my cast iron risers totally fur up, and needs replacing £500 for a new one from volvo... Grrrr

[@francisc144]

I cannot understand someone spent time and money servicing a project and reused a cheap O ring that cost nothing to replace??

[@Ingeanous]

Hello Francis and thank you for your perspective. As DIY'rs we go into these projects not knowing what we will find and make judgment calls. Little things like O rings for an old engine may be hard to source so we roll with it.

[@francisc144]

@@Ingeanous As a sailor with an engine, one would always carry all common replacement parts for water pump servicing on board. A failed pump would kill your engine for sure.

[@felipe34k]

just dont shut down the engine when it overheats, let it idling for few minutes before shut down

[@Ingeanous]

When there is no water coming out, it's time to shut down immediately.

[@EvertvanIngen]

Look at all that pollution you're throwing in the sea :O

[@abstrahujacod5130]

Green Peace :(

[@stevenroberts2490]

Stoped watching intro too long

[@CessnaPilot99]

Yet you found the time to make a comment

[@Ingeanous]

It was a thing at the time.... @@CessnaPilot99