What is the condition of this Yanmar 3GM30F?

[workmaster2n]

I've just come across a vessel that is for sale interstate. The broker sent along this photo today, along with some other documentation.

The boat was completed in 2002 and the engines have ~1800 hours on them. I think the engines are original. I don't have any experience with Yanmars, so does anyone see anything of concern with the level of rust on this engine? It looks like there is a decent amount of rust on one of the injectors (I think that is what is by the air filter?)?

[Tin Tin]

So there are two engines? Do they have the same hours and what hour meter are your reading them from? 1800 hrs is low for a 21 year old boat with engines that look like that. Maybe a lot of neglect, however it could be mostly cosmetic, wire brush and some Yanmar paint and it will look good as new. Main thing is when warmed up run it at WOT for a 10 minutes and see if it overheats or blows smoke. Check oil level and in sail drive too.

[tkeithlu]

Ditto on Tin Tin. Exterior rust doesn't tell you much about interior condition. The run test proposed will without your doing any disassembly. Also check ease of starting and color of any smooth when starting. Carry your test on through the transmissions and props. Remember that exterior rust could just be a splash of saltwater, or could mean that the engine has been underwater, two very different situations.

Good luck with it.

[GordMay]

Originally Posted by tkeithlu

.. The run test proposed will without your doing any disassembly. Also check ease of starting ...

Start & run tests are best [most revealing] performed on a cold engine.
Feel the engine block, before starting, to see if the owner has warmed it up, prior to your pre-survey.

[NorthCoastJoe]

Agree with all of the above. I had a raw water drip ( 1 to 2 drops/ min ) on a 10 hour run that caused quite a bit of rust on a new engine. I should have done a fresh water rinse when I found the drip.

It is what's going on inside that matters. That engine runs perfect just not so new looking after the drip.

[Iron E]

Originally Posted by GordMay

Start & run tests are best [most revealing] performed on a cold engine.
Feel the engine block, before starting, to see if the owner has warmed it up, prior to your pre-survey.

This is great advice. I've rescheduled inspections due to the owners being at the boat and starting the engine before we arrived.

Also, I'm in the category that believes an engine that looks like that, more likely than not, wasn't properly serviced. I've seen 50+-year-old boats that have pristine engines in engine rooms you could eat off of, with engines that start at a whisper of an ignition key.

Besides the obvious signs like smoke from the exhaust, Internal Engine wear can be difficult to detect, even with fluid lab tests.
Personally, if I saw this engine, I would assume it wasn't maintained.

[Reeve21]

I had a 3GMF 30 that had a raw water drip that led to surface rust--not as bad as this, but it did corrode one of the injector lines (that is probably not the technical term!) to the point where it was better to replace it.

It is a good engine. Be careful when removing the secondary fuel filter canister, it is possible to strip it and end up with a diesel leak.

[skipperpete]

Hmmmm there’s a lot going on with that great little engine, first off , it’s the European model so some of the parts are different.... then there’s a missing head stud on #3 cylinder but more importantly there’s a huge possibility that the lube oil supply pipe is badly corroded. The pipe runs from low on the block near the alternator right around to the front of the engine on the other side, has a wall thickness of about two layers of kitchen foil and is almost NEVER painted. Worse is that it usually corrodes most where it disappears behind and under the starter motor so when it eventually rusts through there is no sign or indication of of an oil leak other than the low lube oil alarm.... or warning light.... if you’re lucky. Getting out stuck injectors from the type of corrosion in your photo can be a daunting task requiring a special extractor and a lot of soaking with whatever release spray you prefer.... and taking the head off is usually a waste of time unless you have to go full medieval and cut the inside end off the precom chamber and press the injector out from that side.

[Iron E]

Originally Posted by skipperpete

Hmmmm there’s a lot going on with that great little engine, first off , it’s the European model so some of the parts are different.... then there’s a missing head stud on #3 cylinder but more importantly there’s a huge possibility that the lube oil supply pipe is badly corroded. The pipe runs from low on the block near the alternator right around to the front of the engine on the other side, has a wall thickness of about two layers of kitchen foil and is almost NEVER painted. Worse is that it usually corrodes most where it disappears behind and under the starter motor so when it eventually rusts through there is no sign or indication of of an oil leak other than the low lube oil alarm.... or warning light.... if you’re lucky. Getting out stuck injectors from the type of corrosion in your photo can be a daunting task requiring a special extractor and a lot of soaking with whatever release spray you prefer.... and taking the head off is usually a waste of time unless you have to go full medieval and cut the inside end off the precom chamber and press the injector out from that side.

Great information.

Doesn't it also look like the exhaust mixing elbow and hose were replaced?

Could this have been caused by a clogged elbow, resulting in the rubber hose blowing?

I would think that a completely clogged exhaust elbow may have been causing prolonged engine overheating

[Wotname]

A dirty rusty exterior might predict lack of maintenance but not always. I have seen enough poor exteriors yet well maintained internals not to pass judgement too quickly. Likewise I have seen occasionally a 'rattle can' overhaul that look great on the outside but the internal condition is beyond terrible.

That said, the missing head stud would strongly suggest to me the engine has had NO maintenance. I can't imagine anyone operating any engine with a missing head stud - really!

The 1800 hours doesn't worry me but the low hours over 20 years does worry me. These are stout engines but they die from the ongoing lack of maintenance, drip by drip!

Skipperpete is right, with the degrees of rust visible in the photo, the external oil feed pipe is going to fail soon because I can promise you no one has looked at it for very long time, if ever.

He is also right, a rusted in injector in these engines can be a bear to remove - as in having to destroy stuff to remove a really bad one. Don't ask me how I know this!

If the engine has no love, you can be sure the sail drive has had even less.

So factor in a replacement engine and sail drive or run, don't walk away.

[Wotname]

Rethinking this - the missing M12 head stud is more likely to be a broken stud and the remaining part well rusted into the block - just another headache to solve.

[Kd9truck]

Hi, Just looked at your Catalina 400 MK II ? on SailboatData.com your hull speed is 8.1 knots with a YANMAR 4JH3BE. 8.1 knots is the max of what you will get if your motor is at 3k rpms with a clean hull, prop and rudder.
Have you looked at the polars for your vessel? Your polars will give you the max of what you can get under sail. This will be a bit harder to find I don’t think you can do better than the listed hull speed (8.1 knots) with your vessel.
Think of hull speed as terminal velocity for displacement hulls, if you have the intended motor (above ) and a fixed prop that came with it you are going as fast as the hull design allows.
*You can go faster than hull speed if you sail and motor at the same time but you will not beat the polars numbers unless you add sail to you vessels plan.

Cheers.

[Fore and Aft]

Does it look like they are using the seacock on the starboard side of the engine for the engine cooling and not the seacock on the saildrive? Not that it matters, I am just curious.
It definitely looks like the exhaust elbow has been replaced and that's fairly common. Maybe she is a well serviced engine, but the odds are it gets no attention until it won't start or overheats. Then the bare minimum is done until the next issue arrives. I would be predicting a repower if I was surveying that, Cat.
WorkMaster what you have to be careful off if you buy the boat is the death by a thousand cuts. I see it so often where money is trickle fed into an old diesel getting repaired and a few years later and plenty of frustration from an unreliable motor you suddenly realise you have spent thousands of dollars on a motor you should have just replaced in the first place.
Cheers

[Fintry]

There has been only a passing mention of sending engine and gear oil samples out for analysis. This won't answer all the questions above, but it gives you a look at anything going on inside.


Jim

[5BTM]

My Yanmar YSB8, 1979 CS27
Hours unknown

Mostly fresh water use, but the previous owner did make it to Matane, Qoebec.