New to forum, anyone out there have a regal 2665 yanmar 240hp.

[Alchemy2665]

Hi,

New to forum, have always enjoyed reading the posts but only now registered.

I have a 2004 regal 2665 commodore with the oceantrac hull and the 240hp yanmar Diesel engine. I'm keen to know if there is anyone else on the forum with exactly the same boat as I'm would like to compare notes on performance stats.

Have tried the regal owners club forum but those Americans just seem to have the big V8's, petrol cost not such an issue I guess!

 

[BartW]

congratulations with the boat, and welcome to the forum,
I've alway's liked Regals and you seem to have a very good find (Yanmar diesel engine in a US boat)

I haven't come across a Regal owner on here recently,
what is her weight ?

I think that 240hp diesel is just OK for this boat, but less then 30kn max speed. (do you really need / want more ?)

If you can just reach max rated RPM at average load, thats the most important thing.
if not, you have to start testing another prop.

 

[Alchemy2665]

Hi, thanks for reply.

My main issue is that at WOT I'm at 3700 rpm, which is 400 rpm over the rated 3300 rpm that the manual states. Admittedly this is with a clean hull/prop and only two on board but with a full tank so I would say medium load. The hull seems to enjoy about 26 knots but that means running at 3500 rpm which I am converned will damage the engine over time due to running at 200 rpm over max recommended. My duo prop pitch is 26 inch and if I go up to the next one which is 28inch it will drop the revs too much and put the engine under strain. I'm guessing that I have the best compromise as the boat is probably suited best to a great big V8 petrol which most of the American boats have.

Am I worrying unnecessarily?

 

[paultallett]

Hi and welcome.

I guess the first thing I'd check is that the tacho is reading correctly as you could be worring about nothing. Once you know where you stand you can start to decide what route would be best for you.

Good luck.

 

[Alchemy2665]

Hi and welcome.

I guess the first thing I'd check is that the tacho is reading correctly as you could be worring about nothing. Once you know where you stand you can start to decide what route would be best for you.

Good luck.

Hi,
I have had the tachometer checked and it is reading pretty accurately about 50-80 rpm over at various different rpm. The prop is the original factory supplied and the throttle stop has still got the lead seal on it so that hasn't been tampered with. I'm coming to the conclusion that when I have a light load I have got to limit the rpm myself and just accept slightly slower speeds.

 

[BartW]

My duo prop pitch is 26 inch and if I go up to the next one which is 28inch it will drop the revs too much and put the engine under strain.

how much was WOT RPM then ?
what do you mean by "put the engine under strain" ?

I think that going over max RPM will put a diesel engine over stress (I'm no expert)
have you looked at the power and torque curves ?
these are usually published in brochures,

I would expect that this engine has a very good torque (power ratio) around 2500...2700 RPM, a good cruising RPM imo

Again, I don't know the yanmars, and am no expert,
just a bit of experience with Volvo's in a similar sized boat.

 

[Alchemy2665]

how much was WOT RPM then ?
what do you mean by "put the engine under strain" ?

I think that going over max RPM will put a diesel engine over stress (I'm no expert)
have you looked at the power and torque curves ?
these are usually published in brochures,

I would expect that this engine has a very good torque (power ratio) around 2500...2700 RPM, a good cruising RPM imo

Again, I don't know the yanmars, and am no expert,
just a bit of experience with Volvo's in a similar sized boat.

The published power curves etc show 3300rpm giving max 240 hp WOT with a fully loaded boat, but in reality my WOT is 3700. If I move up to 28inch pitch this will drop the WOT to around 3000RPM which is too low and I doubt I'd get the boat on the plane. At present my minimum cruising rpm is 3000, any less the boat slows too much and comes off the plane.

My question really is will running the engine at 3500 rpm when the brochure states max 3300rpm do it any harm?

 

[rhino_mac]

I have the same Yanmar diesel in my Monterey 250/275cr (27.5' overall so I'm guessing about the same size boat).

WOT on mine is around 3700-3800 and I think I'm around 32 knots at that rpm. It's definitely more than the 3300 you mention. I'll need to check next time I'm out as I've just fitted a new plotter than isn't situated by my left knee (and therefore impossible to read). Certainly on mine, the engine seems very happy at that sort of speed. In fact, I would suggest the throttle is not quite fully forward. At displacement speeds I can see 2500+ rpm at about 9-10 knots (not that that's a particularly pleasant experience) until I get up onto the plane. Poole Harbour limit is 10 knots so it's a trade off getting out of the harbour quickly and burning through fuel).

On the other hand, I find WOT pretty stressful (and expensive) after a short period so I tend to throttle back to around 22-25 knots which is a nice comfortable cruising speed. WOT is fun for a bit of a blast so I wouldn't use it for long stints anyway.

 

[Alchemy2665]

Thanks rhino_mac. Those stats seem very similar to mine, almost identical in fact, out of curiosity what's the rpm when your cruising at 21/22 knots? I agree that any speed between 7/8 knots and 19-39 knots is noisy and expensive! From the sounds of it I have nothing to worry about, just need some sun to enjoy the boat!!

 

[rhino_mac]

It's difficult to tell as my old plotter was in such a bad position I never really turned it on. You'd have to bend down to your knees to see it which isn't really great at that speed. It's also been a while since I used the boat as I only bought itlast July and winterised it in November. The "speedo" on my boat takes ages to react to any change in speed so is pretty useless (think it works off hull pressure or something).

But from memory, I would guess I'm at about 2800-3100ish at 21/22 knots, rising to about 3800 at between 32 and 34. Depends how calm the sea is and how well I've trimmed everything up.

I'll check for your exactly next time we get a decent bit of weather as it's ready for the water again now.

 

[rhino_mac]

I'd also add that my boat too is very sensitive to load. I went out in November with 4 kids, 3 adults and a full tank of full and getting it onto the plane was a right effort. 2 adults and half a tank and it's easy even without trim tabs.

 

[Alchemy2665]

That's great thanks, let's hope we get a better summer so we can enjoy our American cruisers with the canopy down!!

Re the speedo, if you have a look at the back of the leg, just above the gear box you will see a small hole, about 3mm. That is the intake for the water which works the speedo. They always get blocked up and stop working, if you clear it you will probably find the speedo works better, although it will never register anything until you are on the plane anyway. Now you,ve got your GPS away from your knees life should be a bit easier.....why do people put them in that position

Look forward to hearing from you when you've had your first outing.

 

[Alchemy2665]

I'd also add that my boat too is very sensitive to load. I went out in November with 4 kids, 3 adults and a full tank of full and getting it onto the plane was a right effort. 2 adults and half a tank and it's easy even without trim tabs.

Yes, exactly the same for me, max I've had is 8 on board and needed lots of trim and a couple in the cabin to get going, ok once up there though.

 

[Latestarter1]

The published power curves etc show 3300rpm giving max 240 hp WOT with a fully loaded boat, but in reality my WOT is 3700. If I move up to 28inch pitch this will drop the WOT to around 3000RPM which is too low and I doubt I'd get the boat on the plane. At present my minimum cruising rpm is 3000, any less the boat slows too much and comes off the plane.

My question really is will running the engine at 3500 rpm when the brochure states max 3300rpm do it any harm?

You are quite correct in saying that your 4LHA has a rated speed of 3,300 rpm.

However your high idle is 3,685 +- 25 rpm

Yanmar propeller matching rpm is in the range 3,425 - 3,525 rpm

Also remember a Yanmar tacho is hopeless, and always reads optimistic, certainly 100 plus rpm at WOT.

Get yourself a hand held tacho off Ebay and come into the real world!

Sounds like builder has propped to the Yanmar letter. Brillant little motor, but over prop it and it will have the life of a disposible cigarette lighter.

 

[rhino_mac]

OK. Sorry to ask a dumb newbie question but what is a high idle speed?

 

[Beamishken]

the 100% method of propping one of these engines is to test the exhaust gas temperature at the exhaust elbow you fit a probe into the blanked hole & run the boat at wot & record the temperature of the gasses this is the crittical element as if there too hot (engine overloaded) then irespective of wot rpm you engine will be damaged

I guess your on a bravo 3 drive in which case you can either go up to 28" props which should drop wot by 400rpm ish (depending on leg ratio) or fit a set of "cupped" 26's which are roughly equal to 27" pitch & should take 200rpm off your wot

talk to dave crawford marine re exhaust gas temp testing they are very knowlegable on all things yanmar

I have a set of 26" cupped props for sale if you want to go down that route but talk to crawfords first

I was 25 years in the motor trade & I wouldnt be happy running an engine at over max rpm I think the continuous rating on the 4lh is 3100 so your well over that

you should be able to rev past the 3300 but cruise (with throttle backed off) at 3100 or less

pm me if you are interested in the props

ken

 

[Jim@sea]

My duo prop pitch is 26 inch and if I go up to the next one which is 28inch it will drop the revs too much and put the engine under strain.?

I would rather have a diesel running under load at lower revs than revving higher than the manufacturers say and it would be under load anyway.
And how do you know it will drop the revs too much until you try them.
Perhaps your biggest problem would be that at tickover the boat would be more difficult to control in a marina as it would be going slightly faster ?

 

[Alchemy2665]

I would rather have a diesel running under load at lower revs than revving higher than the manufacturers say and it would be under load anyway.
And how do you know it will drop the revs too much until you try them.
Perhaps your biggest problem would be that at tickover the boat would be more difficult to control in a marina as it would be going slightly faster ?

Your right re trying a different prop but with the cost of the bravo 3 props I simply can't afford to buy them on a gamble, hell of a lot of money to waste if they make the boat worse!

Surely Regal wouldn't have supplied a prop that would damage the engine?

 

[Jim@sea]

Your right re trying a different prop but with the cost of the bravo 3 props I simply can't afford to buy them on a gamble, hell of a lot of money to waste if they make the boat worse!

Surely Regal wouldn't have supplied a prop that would damage the engine?

On my last boat I was thinking of putting a larger prop as there was plenty of power lower down but with it not having a turbo it maxed out at 3000 revs. I was advised that my propeller was a "Compromise Propeller" where on putting the gearbox in drive the boat was not going to0 fast at tick over, And it was easy to handle in a marina.
On my present boat (also Yanmar Diesel) it has a BIG 4 Blade Propeller and it is a bit of a handful in a marina because as soon as you put it into drive its doing 5 knots.
But someone else has bought an Identical boat to mine with the same Yanmar engine and has asked how fast my boat went as he was not getting the speed which mine does.
It turns out that although his boat is identical to mine, his is fitted with the smaller 3 Blade Propeller. So perhaps the manufacturer fitted alternative propellers.
Obviously you don't want to buy a set of bravo 3 props and find out they don't make any difference but are there any for sale second hand, you could always buy some and then re-advertise them if they don't work, and if they do work then you advertise the old ones you have taken off. (or put an advert on this forums "Wanted" ie. Wanted to Hire at £200 for 1 week. then state the pitch of propellers you want)

 

[Latestarter1]

I would rather have a diesel running under load at lower revs than revving higher than the manufacturers say and it would be under load anyway.
And how do you know it will drop the revs too much until you try them.
Perhaps your biggest problem would be that at tickover the boat would be more difficult to control in a marina as it would be going slightly faster ?

It is exactly the reason why Yanmar went to the trouble to publish a 'judgement standard for propping' of 3,425-3,525 rpm to combat this type of bonkers thinking. This is a typical high output marine engine delivering almost 70 hp/liter and in it's time was 'best in class' For the last time, overloading high output engines engines simply wrecks them. It appears that posters who claim to have been in the motor trade for x many years made a good living but never learned squat all about diesel engines.

To address question on 'High idle'. Maximum power is achieved at 'rated speed' however marine governors are not set to hit a brick wall at rated speed (isochronous) fuelling and power is progressively reduced out to the governor break point at which fuel is cut off, in the case of Yanmar 4LH is 3,685+-25 rpm or high idle. Simply the opposite to low idle, not 'tickover' that is a term reserved for stationary steam engines.

If, as I suspect tacho is 100 rpm optimistic vessel is propped exactly to Yanmar 'judgement standard'.