Determining KM35A marine gear oil level.

Aug 26, 2019
10
Hunter 41 DS Trenton
We have an H41 DS with a 4JH4AE motor turning the prop through a KM35A marine gear. Manual doesn’t list this particular engine/gear box combination but does say to check the gear oil by removing, wiping and then fully reinserting the dip stick to determine the oil level. Question - do you screw the dipstick in to fully seat it or do you just rest it on top of the housing to determine the correct oil level?
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
  1. Make sure engine is level.
  2. Remove the filler cap (Figure 7, (1)) at the top of the housing.
  3. Remove dipstick (Figure 7, (2)) and wipe with clean cloth.
  4. Re-insertthedipstickwithoutscrewin. See the illustration (Figure 7).
  5. Remove dipstick. The oil level should be between upper (Figure 7, (3)) and lower (Figure 7, (4)) lines on the dipstick.
  6. Screw in the dipstick.

page 44:
Checking Marine Gear Oil
 
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Aug 26, 2019
10
Hunter 41 DS Trenton
Thanks for the great response jviss. Although the engine/gearbox combo’s are not the same as mine I suspect the manuals have been updated to clarify the process. This is a new to the us boat but it looks like we’re running with low gear oil. Our oil just shows on the dip stick when “fully inserted” (screwed in) so I’ll top it up without screwing in the dip-stick. Again, thanks for your quick response!
 
Aug 26, 2019
10
Hunter 41 DS Trenton
Nope - doesn’t include it specifically but I’m going with the manual you provided unless I hear otherwise.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
The KM35A and KM35A2 are identical except the latter is strong and has a slightly different reverse gear ration; otherwise, they are identical.

Good luck.
 
Aug 26, 2019
10
Hunter 41 DS Trenton
Thanks again. I’m in Canada - is the specified gear oil automotive oil with an SAE 20 or 30? Any marine gear oil I find is typically around a 90 weight.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Thanks again. I’m in Canada - is the specified gear oil automotive oil with an SAE 20 or 30? Any marine gear oil I find is typically around a 90 weight.
It's not a gear oil, it's simply 20 weight or 30 weight non-detergent motor oil; i.e., not multi-weight like 10W30, and with no detergent additives. It's commonly used in lawn mower engines, and should be available anywhere motor oil is sold. It seems crazy expensive in Canada, though, form what I can see. Here in the US a quart is about $7. Might try Amazon.
 

NYSail

.
Jan 6, 2006
3,048
Beneteau 423 Mt. Sinai, NY
Just plain 30 weight oil......... not gear oil like was said
 
Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
Thanks for the great response jviss. Although the engine/gearbox combo’s are not the same as mine I suspect the manuals have been updated to clarify the process. This is a new to the us boat but it looks like we’re running with low gear oil. Our oil just shows on the dip stick when “fully inserted” (screwed in) so I’ll top it up without screwing in the dip-stick. Again, thanks for your quick response!
I would also recommend extreme caution when screwing the dip stick back in. As you know, the threads are a sort of plastic and it is very, very easy to cross thread and strip the plastic. I lubricate the threads and carefully counter rotate the threads very slowly until I feel the threads seat. Then very gently tighten it, and not too tight.
 
Aug 26, 2019
10
Hunter 41 DS Trenton
I know. Crazy price - and especially so given I’m Canadian so all in, with exchange and shipping it was $140.00 CAD. However - after reading the posts from those who have gone through the “dissolving” OEM version, I swallowed hard and then hit the order button. I’d rather not worry about it.
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
I know. Crazy price - and especially so given I’m Canadian so all in, with exchange and shipping it was $140.00 CAD. However - after reading the posts from those who have gone through the “dissolving” OEM version, I swallowed hard and then hit the order button. I’d rather not worry about it.
I get that. I would probably have done the same thing.

I think it's cool that this enterprising fellow knew of or experienced this issue, and had the knowledge and facilities to draw up a CAD model and CNC machine this. And, do a nice job anodizing it.
 
Aug 26, 2019
10
Hunter 41 DS Trenton
Absolutely agree. I don’t mind paying for quality and after getting one in my hands to see for myself, I don’t regret the purchase.
 
Dec 25, 2000
5,703
Hunter Passage 42 Shelter Bay, WA
Thanks again. I’m in Canada - is the specified gear oil automotive oil with an SAE 20 or 30?
The bell housing on our 1991 4JH2-TE states the type of lubricate required for our Kanzaki transmission. In our case it takes ATF. The owner's manual says engine oil, but the service manual and bell housing plate says ATF. The PO used engine oil and that is what the transmission had in it when we took possession. It now has ATF. Be sure to check.
 

MitchM

.
Jan 20, 2005
1,011
Nauticat 321 pilothouse 32 Erie PA
wouldn't you think yanmar could be clearer in their instructions that you do NOT screw the trans fluid dipstick 'all the way in ' to check fluid level? and also warn people NOT to screw the plastic dipstick back in to a hot gearbox because you can (and likely will) break the cheap plastic ?....
 
Aug 13, 2012
533
Catalina 270 Ottawa
Another heads-up: transmission takes very little oil (usually, well under 0.5 l (my ZF50 uses 0.35 l in total)), so be careful when you top up. I suggest a syringe.