Yanmar 3YM20 or Beta 20?

[Trident]

I need to repower and will get one of these - I can get both at so close to the same price that its not a decider and they have 1 hp difference in power and 4 ft lb more torque to the Yanmar but for 0.2L / hr greater fuel consumption - its a bit more fuel but again not enough to go one way or the other.

What really matters to me is a) reliability which reports show as very good for both and b) noise and vibration

I've watched video of both and its hard to see a difference but with mobile phone video sound is always poor so has anyone direct experience of both ?

I've heard people be very impressed by the smooth running of the Beta but can't find much about the Yanmar in this respect and my experience is only of the much older 3GM series which are very noisy and rattly - will the 3YM20 be better than the older ones?

Any feedback is gratefully received

 

[RichardS]

My feeling would be that the Yanmar would be the better choice if you can get them at the same price, which, in itself, surprises me. I suspect that parts availability and expertise etc in the Med will be better for the Yanmar.

Richard

 

[Trident]

I should say the work is being done in the UK before a return to the Med and then the Caribbean but that is a good point thanks

 

[awol]

I re-engined with a 3YM20. Decision parameters as well as price were physical dimensions, engine bearer compatibility, existing services of seawater, diesel and calorifier connections. As to smooth running, I have to remind myself to turn it off, it is just too easy to leave it idling.

 

[ianc1200]

I've got a Cornish Crabber which I put a 2YM15 in 2013, and a bawley yacht which I put a Beta 20 in 2016. So not a direct comparison, but both appear to be really good engines. I wanted to have a more powerful alternator on the Beta (can you do that for the Yanmar?) but didn't trust the Beta's standard gearbox, the TMC, so also paid extra for a PRM. I suspect if push came to shove I'd go for another Yanmar.

 

[Trident]

I wanted to have a more powerful alternator on the Beta (can you do that for the Yanmar?).

Weirdly the Yanmar now comes with a 125Amp Alternator which seems huge for a 21 hp engine so I was actually thinking of seeing if they could do a smaller one like a 65...

 

[PetiteFleur]

When I was researching new engines a few years ago, I looked at all the various makes - 25hp - I decided against the Yanmar as there were no options at all and the sea water pump was difficult to get at, whereas with the Beta, they made custom engine mounts to suit my bearers, sea water pump was easy to get at, DIY installation allowed(with final inspection by Beta dealer), many more options, good price and very good to deal with. I've been pleased, now with well over 1000 hrs.

 

[RichardS]

When I was researching new engines a few years ago, I looked at all the various makes - 25hp - I decided against the Yanmar as there were no options at all and the sea water pump was difficult to get at, whereas with the Beta, they made custom engine mounts to suit my bearers, sea water pump was easy to get at, DIY installation allowed(with final inspection by Beta dealer), many more options, good price and very good to deal with. I've been pleased, now with well over 1000 hrs.

The Yanmar range with the difficult to access seawater pump was the older GM range. The pump on the YM range is easy to remove, possibly depending upon how the engine is mounted in your boat, of course.

Richard

 

[jwilson]

The Yanmar YMs are nice enough engines, reasonably smooth and quiet. I have an early 3YM30, but spares are expensive for what they are, especially engine mounts at £800+ a set that they say should be changed every 1000 hours/four years.

I was rather put off Yanmar by them not issuing a recall for the early (first 5,000-odd) 3YM30s that overheated if run at moderately high revs. They just waited till owners complained, before changing the heat exchangers for higher capacity ones as fitted to the newer engines.

YM water pumps easy access at front: oil filters at side, starter motor a swine to change on my installation and mine is now on it's third. Also on third exhaust elbow, 2nd alternator, 2nd set of crankcase oil seals and now again leaking oil slightly. If re-engining I'd be highly tempted by Beta or Nanni, as most parts are basic industrial Kubota of which many more blocks are in use worldwide.

 

[macd]

When I was researching new engines a few years ago, I looked at all the various makes - 25hp - I decided against the Yanmar as there were no options at all and the sea water pump was difficult to get at, whereas with the Beta, they made custom engine mounts to suit my bearers, sea water pump was easy to get at, DIY installation allowed(with final inspection by Beta dealer), many more options, good price and very good to deal with. I've been pleased, now with well over 1000 hrs.

Yes, the ability to customise the Beta can be very attractive in many installations, and not least with the custom bearers you mention. After-sales service from the factory is also excellent, as repeatedly testaments on here make clear. Beta parts prices are also significantly less giddy. Beta offers a 5-year warranty, even if owner-serviced. (And they're happy for the installation to be signed off by any marine mechanic: no need for an authorised dealer to do so.)
None of this is to denigrate Yanmars, which are excellent.

 

[Lightwave395]

Replaced my 3GM30 with a 3YM30, different world with the new one - quiet, powerful and economical, plus old one out, new one straight in with no fuss in a couple of hours.
The alternatives I looked at all needed quite a bit of work to fit

 

[doug748]

.....

Any feedback is gratefully received

It was no contest for me because all of the class were fitting one type of engine so, with one eye on resale value, there was only sensible solution. Think about where, in the fullness of time, you may want to dispose of the boat; in the Med and elsewhere, a Yanmar might possibly have the edge, in the UK, or States, then Beta comes more into the picture.

As suggested, check out spares. I just replaced my Beta stainless high rise exhaust which was a little over £200, the Yanmar equivalent seems only a tiny bit more expensive. However Yanmar engine feet must be gold plated whilst the Beta ones are pretty common across the range and come in at c £35 each.

 

[CJ1]

I have recently bought a Moody 27 that came with a 4 year old Yanmar 3YM20.

The engine has performed fine during the one season I have had it.

But there have been two problems.

1. The rev counter stopped working, and when I asked the company who fitted the engine about it they said "Yes, the engines are susceptible to that problem"

2. I've got a suspicion that it does vibrate rather too much. I have just noticed that two battery switches (see photo) attached to a bulkhead in the engine compartment have cracked, and I guess this must be due to excessive vibration.

I don't know whether these problems are because of my particular set up, or whether they are common to the design.

 

[RichardS]

I have recently bought a Moody 27 that came with a 4 year old Yanmar 3YM20.

The engine has performed fine during the one season I have had it.

But there have been two problems.

1. The rev counter stopped working, and when I asked the company who fitted the engine about it they said "Yes, the engines are susceptible to that problem"

2. I've got a suspicion that it does vibrate rather too much. I have just noticed that two battery switches (see photo) attached to a bulkhead in the engine compartment have cracked, and I guess this must be due to excessive vibration.

I don't know whether these problems are because of my particular set up, or whether they are common to the design.
View attachment 81559

The cracking is more likely to be due to over-tightening.

In my experience, give a plastic fitting to a typical auto or marine mechanic with a screwdriver or spanner and you will end up with a cracked fitting. :ambivalence:

Richard

 

[pvb]

Weirdly the Yanmar now comes with a 125Amp Alternator which seems huge for a 21 hp engine so I was actually thinking of seeing if they could do a smaller one like a 65...

It most probably won't make any difference, in terms of overloading the engine, unless you have a huge battery bank. Batteries will only accept a certain amount of charge, regardless of the theoretical capability of the alternator. Having a higher-rated alternator can be a distinct advantage, as it will usually provide a reasonable charge current at lower revs.

 

[Praxinoscope]

I’d go for the Beta everytime, I fitted my last boat with a Beta 10 which performed fantastically over the 20 years that I had the boat, my new boat has a Beta 14 which is just as good.
The guys at Beta are also great to deal with.

 

[ithet]

I need to repower and will get one of these - I can get both at so close to the same price that its not a decider and they have 1 hp difference in power and 4 ft lb more torque to the Yanmar but for 0.2L / hr greater fuel consumption - its a bit more fuel but again not enough to go one way or the other.

Unless you actually use the extra 1hp (i.e. run flat out) you will not use the extra 0.2l as it corresponds to the fuel required to deliver that extra 1hp.

 

[Trident]

Unless you actually use the extra 1hp (i.e. run flat out) you will not use the extra 0.2l as it corresponds to the fuel required to deliver that extra 1hp.

The fuel consumption difference is based on a direct RPM comparison - the Beta and the Yanmar make the same power almost exactly at 2000 rpm but the Yanmar uses 200ml more fuel there BUT makes 4 ft lb more torque so is putting more power in to the prop for that fuel which means of course in the real world I may get the same boat speed at slightly lower revs with the Yanmar so the difference is probably not a major issue in the real world

 

[ithet]

The fuel consumption difference is based on a direct RPM comparison - the Beta and the Yanmar make the same power almost exactly at 2000 rpm but the Yanmar uses 200ml more fuel there BUT makes 4 ft lb more torque so is putting more power in to the prop for that fuel which means of course in the real world I may get the same boat speed at slightly lower revs with the Yanmar so the difference is probably not a major issue in the real world

Yes, in the real world your prop curve would be well below the max power curve at 2000 rpm so the difference is negligible as you say. In theory you could fit a slightly higher pitched prop to the Yanmar to get the slightly lower revs.