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

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

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.

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!

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.

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

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

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

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.

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

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

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

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

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.

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

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.

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.

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????

routine maintenance beats alarming failures every time

A very informative video. 👍🏿

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

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. 🖒

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.

Thanks for the video, very helpful.

Thanks ! Great video, really helpful.

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!

The best informative video. Thank you so much

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.

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

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.

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

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

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.

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

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

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

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.

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

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

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

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

thank you!

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.

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.

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

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

Beercan island? Sounds like a great place

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

Nice!!!!

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

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 ;-)

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?

Invest in a good set of socket extensions.

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?

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?

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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.

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

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

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!

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

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

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

Did you check your intake?

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

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

Barnacle buster helps marine engines.

BFS screwdriver. 😁👍

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

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.

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

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

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

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

Green Peace :(

Stoped watching intro too long