Yanmar 2qm20 transmission issue.

[mpjune]

I have a Albin 25 restoration project that the previous owner installed a Yanmar 2qm20 in.

Engine starts and runs like a champ. Shifting though not so much.

The transmission is the original with a long shifting lever on the port side and kind of a round bell housing. I have been trying to find out what this type of tranny is called. I am pretty sure it is not a Kansaki.

It is stiff but shifts into F and R, but when in Fwd and I attempt to pull it back into neutral the shift lever stops at about the neutral position (stilI in gear). If I push the gear lever back forward there is a loud click and then it shifts into neutral.

I know nothing about the workings of this transmission and need a course of action.

Is this an adjustment issue that a good tech can fix, or is this a possible rebuild or replace situation?

TIA

[Wolfe10]

Have you verified this is an issue with the transmission and not a stiff or binding cable?


Can you disconnect the cable and shift the transmission by hand? With the cable disconnected from the transmission, does the lever/cable move freely?

[mpjune]

It is without the throttle/shifter control attached.

I just replaced the controller and cables as part of the restoration project. Getting closer to having it right but still working through the bugs.

This issue is definitely in the transmission.

.

[skipperpete]

Firstly, a disclaimer, I haven’t rebuilt one of this specific model and it’s very different from the usual 2 other QM reversing gears. I just had a browse through the service manual and found the bit about the neutral adjuster with the caution about breaking the spring if adjusted carelessly. Do you have the 2QM workshop manual? all the gearbox instructions are included in that book.

[mpjune]

I haven't invested in any manuals yet but that sounds like the first step in a plan of action.

You just gave me the hint that it is correctable through an adjustment which is what I was hoping for. A workshop manual will be worth the investment. Thank you.

Do the have a name for this type of transmission or is it just a Yanmar?

I see many references online to Kanzaki but have been unable to find a name or model number for this one.

[Wotname]

What is the exact model number of the engine?

The various gearboxes originally supplied are as follow

2QM20 - YP-7M
2QM20B - YP-10M
2QM20H - KBW10A
2QM20Y - YP-10M
2QM20F - KBW10A

[skipperpete]

Originally Posted by mpjune

I haven't invested in any manuals yet but that sounds like the first step in a plan of action.

You just gave me the hint that it is correctable through an adjustment which is what I was hoping for. A workshop manual will be worth the investment. Thank you.

Do the have a name for this type of transmission or is it just a Yanmar?

I see many references online to Kanzaki but have been unable to find a name or model number for this one.

You have a choice of either the YP7M on the earlier 2QM20 ……but later engines used the YP10M that was fitted to many of the 3QM30 engines (until the arrival of the Hurth Kanzaki gearboxes)
The manual download might be available in the CF publications section.

[Wotname]

The adjustment method for the YP7M and the YP10M. The size and shape shifting lever is the easiest way to determine which one you will have.

[skipperpete]

Originally Posted by Wotname

What is the exact model number of the engine?

The various gearboxes originally supplied are as follow

2QM20 - YP-7M
2QM20B - YP-10M
2QM20H - KBW10A
2QM20Y - YP-10M
2QM20F - KBW10A

Hey , thanks Wottie, I went out to get a coffee half way into my reply and missed that you’d already posted the info.

[mpjune]

It is a 2QM20 so it is a YP-7M.

ThankYou!

[Wotname]

Have you checked the oil level?
Also unless you have replaced the transmission oil, don't assume the existing oil is the correct type.

EDIT - The transmission oil should be of the same type as the engine oil.

[mpjune]

Sorry it took so long to close this thread but thank you for the advice and assistance from everyone.

After reviewing the manual I removed the shifter cover/housing and discovered the shifter bushing (bronze) had both sides broken off (see photo). In addition to that damage the parallel pins were both worn almost all the way through due to metal on metal rotational contact. Actually I am not sure how it shifted at all.

Parts were all available until they weren't.

Ordered from supplier and he had to order them from their supplier (35 on hand). Their supplier must have had an inventory glitch so they had to be ordered from Japan. Finally arrived yesterday.

Seems to be much quieter and shifting much better but still a bit tougher than I like. I am planning on using it for the summer and then taking the whole boat in for an evaluation at a marine shop.

However this forum got me back on the water for now. Thank you all for your input.