Tor,
Installed the 4JH4AE last winter. Didn't get a lot of use over the summer, but mostly motored from the Chesapeake Bay to Marsh Harbor, The Bahamas. Current engine hours; 270

Engine RPMs at idle: 700; at cruising: 2000; at full throttle 2900
Cruising speed (flat water): 6.8 kts; full throttle: 8 kts
Prop size & Pitch: Maxprop 20″. Don't know the pitch. We set it originally to PYI specs for the Yanmar then had to reduce it after sea trials because we couldn't get over 2500 RPMs. I just realized I didn't get the mechanic to write down the final settings for the Maxprop (which have to be converted to pitch).
Dont' really have good metrics on on consumption, but it appears to be a little more than the W60. i'd guess a little less than 1 gal/hour at cruising rpms.

John

On Mon, Jan 26, 2009 at 10:00 PM, Silver Heels < ([email][/email])> wrote:

Would appreciate hearing from any and all who have a Yanmar 4JH4E in their P424. Specifically wish to know:

– What are your engine's RPM's at idle, cruising speed, and full-throttle?
– What are your boat's cruising and full-throttle speeds under power?
– What is your prop size and pitch?
– What is your average fuel consumption rate at cruising speed?

Thanks,

Tor
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Silver Heels, P-424 #17
http://www.SilverHeels.us
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Regards,
John Stevenson
http://www.svsarah.com

Post generated from Pearson424 Forum using Mail2Forum

Hi,

i just installed one a couple of weeks ago, so little info on consumption, but I idle at 700 RPM, cruise nicely at 2200-2400, start cavitating then and have vibration. I do around 6 knots at crusing depending on wind and sea conditions and have not yet experienced flat seas..currently in St.Lucia. I have a Prowell prop, 18.5 inches and 13.5 pitch.

Joe,
Half Moon

— On Tue, 1/27/09, Silver Heels <> wrote:

Joe,
Assuming that you still have a 2:1 gear reduction, your shaft speed at your cruising RPM is close to where it will start to cavitate. A 13.5 pitch sounds a little bit on the high side, but you note only a 6kt cruising speed at that setting. I have the same diameter propeller but only an 11 pitch. I get about 7.3 kts at 1200 shaft RPM. Something doesn’t add up. If you had a lot of growth on your hull you might get only 6kts.

If your V-drive is properly aligned and your shaft and prop are in good condition, you should experience a little vibration at that shaft speed, but not enough to rattle dishes. At 1200 shaft RPM, I can feel vibration in the soles of my feet if I stand in the aft cabin, but nowhere else. Dishes nor doors rattle. I’ve had to play with the engine alignment to get the boat to run smoothly.

Rich

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I installed one 2yrs ago cruise @ 2200 to 2600 rpms speed 6 to 7 knots fuel consumption about 1/2 to 3/4 gals per hr used original prop had work done on it to yanmar spec’s after sea trials had to work the stringers for eng mounts as they were tilted out bd. on both of them installed a new fuel tank @ the same time rebuild trans. v drive seems to be fine all in all very happy with it.the hardest part was the exhaust oh yes while having new fuel tank built to 3 to 5 inch shorter from top to bottom so it can be removed with out removing engine lost like 15 gals capacity.but can be taken out from laseret.also lost aweight in stern due to eng wieght and loss of fuel weight but with the dingy on the davits and people in the cock pit weight seems to distribute better I’m thinking of installing a gen set in the rear laseret to even the weight of the bow Some times depending on where I’m headed to and for how long I leave the bow water tank with only half full then use that tank first allways to even the wieght.because just aft of the forward water tank I have the bow thruster and a 8d battery for the thruster and windless.

Don B
Thisisit
# 81 sloop
Mystic Ct.

<.. snip>

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Tor
I will check with the paper work or the mech Dale @ fort Rachal who did the work and let you know in the mean time i will loook for all the pic’s and forward them to you.Full load he says 3000 rpm’s but I do not GO OVER 2800 I tried 3000 and in about ten min. of that I saw the heat gauge start to go up so for mine with the pitch I say 2800 is max and just fine I can move along @ a comfortable 7.5 knots or slower faster depending on the current speed with me or against me

Don
Thisist
#81 sloop
Mystic Ct.

<.. snip>

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I’m in the caribbean now, with Chistmas winds blowing. I motor only when I have to..maening into waves and winds..so 6 kts is ok with me. I’m sure I;ll get more in calm seas and fair winds..but let me know what Yanmar says, I was planning to write to them to get their recommendation on prop sizes and pitch, ranges that are acceptable with a 2:1 V-drive. But I haven’t done that yet. Yes, Prowell is a prop that feathers ( most of the time).

— On Tue, 1/27/09, Silver Heels <> wrote:

I had somewhere read that diesels can run at WOT but that it is adviseable to run at 80% of that rate, i.e. 2400RPM in the case of the Yanmar. Am I misinformed??

Joe,

— On Wed, 1/28/09, Silver Heels <> wrote:

Rich,

I’m sorry to have incorrectly stated my prop had a 13.5 pitch..it’s 12.5. The original 3 blade prop is 13.5 with a 20″ diameter. My Prowell is 18.5 x 12.5.

I’m not really sure if the vibration I feel at RPM over 2400 is due to caviation or something else..I assume it’s cavitation. I’m not sure how to tell for sure..but my speed does not increase appreciably when I go above 2400 so I assumed I’m getting caviation. I suspect my cutless bearing may need to be replaced..so that could e a source of vibration too. I just do not like to feel vibration in my feet since that means something is wearing more than it should.

Also, since I use the engine to go hard to windward mostly, I think going 6kts against wind and seas is not too bad and similar to what I got from my previous Perkins 4-154.
My Yanmar is only 54HP.

Your thoughts?

Joe,
Half Moon

— On Tue, 1/27/09, <> wrote:

” For prolonged running, a pleasure boat engine a good operating speed is around 85% of maximum continuous rated RPM (see the engine data plate) assuming the propeller size is correct and the engine can reach maximum rpm).”

NOTE: the tach will read 100 RPM high at the high end of the scale, so if the tach says 2900 RPM, its really running 2800 RPM.

More info at:
http://www.yanmarhelp.com/operate.htm

Rich
BlackSheep #47

Post generated from Pearson424 Forum using Mail2Forum

Joe,
I checked my notes and see that my prop is 18.5 x12, so our props are almost the same size. There may be some slight difference in efficiency between the two. I have a 3-blade folding Slipstream prop. Since the props are almost the same, the boats should behave the same at the same shaft speed. My gear reduction is 2.5:1 whereas yours is 2:1. I have a much faster turning engine so its geared down a little more. You can view my boat performance at various engine speeds at the link below. Divide my RPM numbers by 1.25 to get your RPM numbers.

My sea trial was done on a calm day in a protected bay. The bottom was clean. There was a little current, so the test run numbers differ slightly between the runs. I get to 7 kts at about 2500 RPM. You should get to 7kts at about 2000 RPM. I can push into a head sea against the wind if I push the throttle up a little. I don’t have figures for boat speed vs engine RPM. I would guess that 3000 RPM will push the boat to 7kts against anything reasonable. This would be about 2400 RPM for your engine.

I can run the engine all the way up to 4000 RPM, but I don’t go much faster. I run it for about 20 minutes at about 3700 RPM about once a month for maintenance.

As I mentioned before, I had to play with the V-drive alignment to get the engine to run smoothly. Even at 4000 RPM, the boat doesn’t vibrate much. If you want some help aligning your V-drive, give me a call any evening at my cell below between 7pm and 9pm Eastern time.

Rich
603-493-3330

Post generated from Pearson424 Forum using Mail2Forum

Thank you, Rich. Now where can I get the data to determine how well my prop fits with my engine/tranny combination?

Joe,

— On Fri, 1/30/09, <> wrote:

Joe
I worked closely with my prop manufacturer to come up with what should have been the proper size for my boat. I don’t believe the size is correct however. Once you install the damn thing and launch the boat, its pretty hard to pull the boat and send the prop back for rework. I’ll live with what i have. Its close enough. I should have a little more pitch. I can overrev the engine at full throttle.

The only way to really tell is to run your boat under power. If you can drive your boat to more than 7.3 kts (hull speed) at less than 85% max RPM, and if you can’t over-rev your engine at full power, your prop is the correct size. I’m somewhat over-engined. I can get hull speed at 64% max RPM. If the prop had a little more pich, I could probably do the same at 60%. With a properly matched propeller, I think you’ll find that your engine drives your boat well.

In order to activate my Yanmar warranty, I had to pay Yanmar to take my boat out for a sea-trial. I’m surprised that you didn’t have to do the same thing.

Rich

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