Installing a 3JH4E *^%#! Yanmar (Rant)

[knottybuoyz]

Originally Posted by delmarrey

TI would like to put in one of these (Pythondrive The ideal flexible and vibration-free drive unit) but the distance between the seal and the coupler is a couple inches short. I may have to move the motor forward about 3" to get this in.

Keep in mind Del the Python drive likes a few degrees of angle. You can't install it dead nuts straight. It'll take up to 8 degs angle in any direction but that's maxing it out. You could level up your engine a bit too while you're at it.

[Chief Engineer]

Shaft Jumping around/slapping/moving for and aft?

1/8" clearance in stern tube?

Did you increase the shaft size?

You said you made the spacer?

This is a head scratcher for sure?

How much hose do you have on the stuffing box?

Are you using stuffing box hose?

Just questions....

[delmarrey]

Originally Posted by Chief Engineer

Shaft Jumping around/slapping/moving for and aft?
The youtube I posted doesn't give it justice. One thing though, it won't wear a grove in the shaft so easily.

1/8" clearance in stern tube?
That's what came with the boat. it's The very end is about 10" away from the trans coupler, which is too close for as much as the motor moves around.


Did you increase the shaft size?
No! It's always been 1"

You said you made the spacer?
Yep! As a Machinist it was an EZ task and the TIR and parallelism were all within .001". Took me 3 hours.

This is a head scratcher for sure?
Yeah! Like said above I think the stern tube is too small or too close the the motor not allowing for the vibration of the motor.

How much hose do you have on the stuffing box?
It is about 5". It came as a kit - thick wall hose, clamps and stuffing box from BUCK ALGONQUIN (see picture)

Are you using stuffing box hose?
as above

Just questions....
No problem!

I really don't know who had the bright idea to put a 3 cly. yanmar in boats but I'd like to kick'm in the arse.

I called the manufacture of this boat (Dencho Marine) and asked them what motor they are putting in their Choate 40's now, and their reply was the 3JH4E, and that is the only reason I bought the yanmar. If I knew how much they danced around I would have went for something else. VW offered me a replacement that would bolt right in where the old one was but it was 10 more HP which I didn't need. And I asumed it still had the timing belt just like the old one.

With this thing up to about 1000 rpm's, to me, it looks like it's coming off the mounts and that's not even in gear. As the rpm's go up the motor smooths out but not enough to stop the shaft slapping. it's better with the stuffing box but still annoying to me. At 3000 rpm's it purrrrs but cruising speed is at around 2600 (7.5 kt).

[delmarrey]

Originally Posted by knottybuoyz

Keep in mind Del the Python drive likes a few degrees of angle. You can't install it dead nuts straight. It'll take up to 8 degs angle in any direction but that's maxing it out. You could level up your engine a bit too while you're at it.

That should be EZ, just slide it forward 3" and pull out the 1/2" shims I put in to raise the motor and bolt it down as is. Leveling? Not a bad Idea, it's at 12º now.

[Northeaster]

I'd put stiffer mounts in (they work fine on my 25 year old Yanmar 2GM), and keep the Yanmars one's - to put back in, if you have any problems that require warranty!

[DeepFrz]

Actually a 3 cyl. engine should be smoother than a 4 cyl. because they are 120 deg. apart. I am starting to think there is something wrong with the engine.

[daddle]

Yeah, maybe you have a dead cylinder? Does it run like a Harly? ThumpThump...ThumpThump?

[Charlie]

Originally Posted by delmarrey

That should be EZ, just slide it forward 3" and pull out the 1/2" shims I put in to raise the motor and bolt it down as is. Leveling? Not a bad Idea, it's at 12º now.

Don't quote me on this but I thought that yanmar only allowed 8 degrees as their max. I'll look it up when I get to the boat tomorrow for the 4JH4E

[delmarrey]

Originally Posted by daddle

Yeah, maybe you have a dead cylinder? Does it run like a HarlEy? ThumpThump...ThumpThump?

On a brand new motor??? Is it possible?

Cracking the injector lines one-by-one would tell, right?

[delmarrey]

Originally Posted by Charlie

Don't quote me on this but I thought that yanmar only allowed 8 degrees as their max. I'll look it up when I get to the boat tomorrow for the 4JH4E

I looked everywhere to find that info and could not. I even posted the question here and no real answer. http://www.cruisersforum.com/forums/...ing-35395.html

[daddle]

Originally Posted by delmarrey

On a brand new motor??? Is it possible?

Cracking the injector lines one-by-one would tell, right?

That's what I do....HardlEy know if it's proper...

[Charlie]

I found it in a strange place in the manual. It was in the oil cpacity specs. The engine uses less oil at a 8 degree slant then when level. I'll scan and post manana.

[Laidback]

How does that engine run when de-coupled from the prop shaft????

[delmarrey]

Originally Posted by Charlie

I found it in a strange place in the manual. It was in the oil cpacity specs. The engine uses less oil at a 8 degree slant then when level. I'll scan and post manana.

Yeah! I have the same thing in mine but it doesn't specify any max angle. As long as the oils suction screen stays submersed all should be well just like on most any other motor. And that's the reason for deep oil pans on RV motors.

The trany may have issues.

[delmarrey]

Originally Posted by Laidback

How does that engine run when de-coupled from the prop shaft????

It does runs the same in neutral. It's just the prop shaft isn't pulsating fore and aft but it still slaps the stern tube, but lightly now that I've put on a stuffing box.