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Replacing Engine

tfrere

tfrere

Thomas McNulty
I started the replacement of my Yanmar 3QM30 this week. I was going to pull the engine using the boom and come-a-longs but decided it would be safer and faster to use a crane at the boat yard. So, I worked a deal with the yard owner to allow me to disconnect everything, have them remove the old engine with their crane, drop in my new engine to the cabin floor, then tow me back to my marina slip where I would finish the installation. So far, everything is going very well. My boat is back in its slip, I have the new engine in the cabin and I am readying the compartment for the installation.
After the installation, I need to pull the boat, replace the propeller, and increase the size of my engine cooling thru hull.
 
What engine are you replacing it with Thomas?

New? Rebuilt?

Curious minds, and all that ...

Chris
 
I am installing a very lightly used 40 horsepower Yanmar 3JH4E. The engine was removed from a new boat to install something larger. It has 250 hours.
 
This job keeps growing. In addition to a new prop and new thru hull, the new engine has a different coupling, requires 3" exhaust, will need different motor mounts than the ones it came with (unless I cut down the beds),
and relocate fuel polishing system. In addition, I'm installing a new engine compartment light, a shaft saver, and a drip less shaft seal. By the way, I will be able to replace the stuffing box while in the water. I took it off to get an accurate stern tube size and the in-flow of water is manageable.
 
Thomas I will too will be replacing my stuffing box with a PYI dripless. What was the outside measurement of the shaft tube? Is the shaft size 1 1/4" ? Are those two measurements the only ones I need? I changed out my Hunter but that has been some time ago. It is a great system and I never had any problems with it.

Look to hear from you.
 
John,
It sounds as though our shaft tubes vary in size. Mine measured 2.41" but others have said 2.25 and 2.5. I ordered a tube 2-3/8" or 2.375 and hope I'll be able to get it on. The shaft is 1-1/4". You will also need the distance from the tube to your coupling.
 
Here is a photo of the finished product
The new engine is a Yanmar 3JH4E rated at 40 hp with a 2.6:1 gear.
As you can see from the photo, it is mounted on 4 x 4 x 3/8 aluminum angle.
I am very pleased but still have not replaced the prop and larger intake thru hull.
image.jpeg
 
Tommy
The engine looks real good.Figured the motor mounts would be a question. Did the engine fit side to side? No problem with the alternator? Does that front plate come off to get to the pumps and belts? Has your prop size changed with the new power?

Jim
 
Jim,
It fit side to side but was too high even without the aluminum with the original Yanmar motor mounts. I purchased some Vetus mounts and it worked out fine. The cover comes off easily with a couple of bolts to access the alternator and belt. I left the 80 amp alternator that was on it but am keeping my 108 amp alternator for when it fails.

My new Kiwi feathering prop should be in today. I was going to use a Max Prop I bought several years ago but am worried about the electrolysis at my marina. The Kiwi is stainless and fiber reinforced plastic blades. If it doesn't work out, I'll get a new bronze fixed blade. A $2500 Max Prop is too expensive to have it deteriorate under water.
 
By the way Jim, it turned out to be quite an undertaking. To make the new engine work, I had to:
Replace exhaust hose to 3"
Replace 2" muffler with 3" muffler
Replace exhaust thru hull fitting
Replace intake thru hull to full 3/4" opening
Replace all four motor mounts
Move fuel polishing to under sink
Replace shaft coupling
Replace control panel

In addition, I installed
A dripless shaft seal
A shaft saver
Aluminum angle on stringers
 
I'd be interested to know the specs for your new prop: diameter and pitch please! (When you know them...)

It remains in the hypothetical future, but I would eventually like to repower Stargazer with something in the ~50HP range.

Chris
 
It depends on the gear ratio. If I was putting on a fixed 3-blade I would expect it to be approximately 16" x 15" That is with a 40 hp engine with 2.6:1 gear ratio.
 
I just recently replaced the Perkins 4-108 with a Volvo D2-40 (40hp) . I elected to use an angled transmission so that the engine sits upright. Since the footprint was slightly narrower on the Volvo I used steel angle. I used steel instead of aluminum so I could weld nuts to secure the motor mounts. And yes I had to cut the stringers to fit. As far as the prop, a Michigan wheel 17x10 with a 2:1 gearbox works just right. At wide open throttle the engine makes 2800 rpm with no overheating. pics to follow.
 
Jose,
It looks like Volvo makes their 40 hp quite a bit more compact than the Yanmar. Do you know how much it weighs?
 
My Yanmar 3JH4E weighs 381 pounds and is rated 40 hp at 3000 rpm.
The engine is surprisingly smooth for a 3 cylinder except at minimum idle it moves a bit.
I really like the physical size of the Volvo. It is narrower but I assume longer since it has an extra cylinder.
 
The Volvo engine is about 30% smaller than the Perkins it replaced. The depth of the oil pan is greater and now the pan underneath is captured in place. I would have to lift the engine in order to remove the pan. Since the motor mounts are held in place by bolts, raising the engine is actually quite easy. If you notice, there is an aluminum pto and hinge mount that extend forward of the block for the water maker pump.
 
464 pounds dry weight without oil or coolant. The transmission is extra weight. It's a bit lighter than the 631 pound Yanmar 3QM30.
 
So do you think we would drop 200lbs if we switched out engines? We don't need to, engine runs fine but we are always looking for weight loss. A new quieter engine might be something that if we do it we want to know what the best replacement would be. I alway felt the 4-108 was a bit under powered in rough conditions
 
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Even though my new engine weighs 381 lbs vs the old engine at 631 lbs the boat sits no differently in the water. It certainly is not worth the time and huge cost of replacing the engine to drop a couple of hundred pounds.
Overall my cost to replace the engine was about $10k. I got the engine for $6k, but had to hire the yard to pull the old engine, replaced exhaust, installed larger suction thru hull, installed new coupling, replaced prop, labor for my mechanic and lots of small item changes.
 
Probably not something we would do right away but you might be surprised, if you raced, (I don't know if you do) what even a hundred pounds less can do especially near the ends of the boat. Dragging sterns slow the boat down. We don't have much weight up at the bow. No windlass, only twenty feet of chain and a light a Fortress anchor.
No big deal, if you are not racing but it all adds up. Changing out our sheets and halyards even made a small difference. Over 12-16 mile race course it adds up let alone some of the 70-100 mile courses. That said I'd rather be able to carry two hundred pounds more supplies etc. have a nice engine like you have but I understand your point. Sounds like you have a great setup. A new engine might not be at the top of our list. A slipping tranny is. Thanks for that info...that's really good to know at any rate.
 
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Assuming you can get 3K or 4K out of your old engine, you are looking at 11K plus taxes for a new engine plus another 6K or more for installation( assuming you don't do it yourself ). All the other things on my "while you are there" list would be about 3K if I had not done a lot myself. Check out your Aqua-Lift platform, mine had almost disintegrated.
The 4108 is not underpowered, you are probably over propped. According to the diesel mechanic and Volvo dealer I got my new engine from, you should be able to achieve the engines max RPM when you run wide open, and the engine should not overheat. In the 4108 this is close to 4,000 RPM,
With the 2:1 transmission ( I am assuming a HBW150 ) at wide open throttle I could not get 2500 RPM, and if left like that, it would start over heating. All of this also depends on your prop, I had the standard 17x10 prop. If you decrease prop diameter or pitch you can get higher RPM, but according to the folks at Michigan Wheel, 17x10 is the right size prop for our boat.
 
John,
Check to see what transmission you have. On the older models they used an HBW 100 . Later they used an HBW150. From what I read, the HBW 100 was a bit too small for the horsepower, it is rated at 30HP. I have an HBW 100 that came off the Perkins, it has low hours since it was rebuilt( due to slipping ), and it is for sale. If I remember right the rebuild was about $400.

Best regards,

Jose
 
Hey Jose...that might be a good idea. I'll be having a look in a couple weeks or sooner. I'll let you know. Atlantic Deisel was my other option. We don't run the engine over 18-2200rpm...usually happens on warm days during July and August...thanks again.
John
 
jose santin said:
John,
Check to see what transmission you have. On the older models they used an HBW 100 . Later they used an HBW150. From what I read, the HBW 100 was a bit too small for the horsepower, it is rated at 30HP. I have an HBW 100 that came off the Perkins, it has low hours since it was rebuilt( due to slipping ), and it is for sale. If I remember right the rebuild was about $400.

Best regards,

Jose
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How much did you want for that tranny? I'll be checking the size this weekend hopefully
 
John,
I would like 300 for the tranny. The engine was 11K. Other things done were: a new shaft, stuffing box, and rebuilding the aqualift platform. I did the install myself. I can tell you that the stringers have to be cut and the steel angles have to be shaped to the hull curvature. I guess 5K to 7K additional labor to get that done.
 
jose santin said:
John,
I would like 300 for the tranny. The engine was 11K. Other things done were: a new shaft, stuffing box, and rebuilding the aqualift platform. I did the install myself. I can tell you that the stringers have to be cut and the steel angles have to be shaped to the hull curvature. I guess 5K to 7K additional labor to get that done.
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Thanks Jose...let me see which tranny we have. Might be a lucky find for us!
I'll try to check it tomorrow when we launch
 
I had to get a mirror and try to read it backwards but it looks like it says HBW 10 followed by some characters I was unable to read. Does that sound like what yours is? Was it rebuilt and ready to go? Thanks
 
This is a picture of it
It has about 20 hrs of run time after it was rebuilt by Palmer Power, the local Hurth/ZF dealer.
 

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jose santin said:
John,
I would like 300 for the tranny. The engine was 11K. Other things done were: a new shaft, stuffing box, and rebuilding the aqualift platform. I did the install myself. I can tell you that the stringers have to be cut and the steel angles have to be shaped to the hull curvature. I guess 5K to 7K additional labor to get that done.
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If it was all installed and looked as nice as yours I'd do it!
 
Let me check with my local guy about installing and see if I can get some help...I'm in Vermont - New York area on Lake Champlain ...did they offer any quarantee with the rebuild? If it all works out i might take you up on it.
I forgot where your at. It'll be next week before I can get an answer from these guys...they are slow to respond in my area.:)
I have some friends I think are near by Houston if that's where your at.
 
The boat is in Kemah Tx. I live on the NW side of town about 60 miles away. The rebuild was done about 5 yrs. ago so there is no warranty. When I sold the Perkins I kept the tranny and a 120 amp alternator( ample power).
 
jose santin said:
The boat is in Kemah Tx. I live on the NW side of town about 60 miles away. The rebuild was done about 5 yrs. ago so there is no warranty. When I sold the Perkins I kept the tranny and a 120 amp alternator( ample power).
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Okay thanks! Let me see what I can find out this week. Thanks for your help
 
wild382 said:
Okay thanks! Let me see what I can find out this week. Thanks for your help
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Jose
I'm not going to get an install estimate till late next week. Sorry, it's the way it is here in the north east. I do have a friend who may help me install it. Just gave to get it looked at first then go from there. Appreciate your patience.
 
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