Transmission issues [Olson 911]

[Bob Izmirian]

I have owned Jane Doe, a 1988 produced O911s, since 1992, and raced her extensively on SF Bay. She's now been detuned and I use her for day sailing with a roller furling no.3 and an asymmetrical kite. Recently, I've encountered what I believe are transmission issues. When the gear lever is placed in forward and throttle applied, the transmission doesn't immediately engage, and when it does, it engages with a jolt. It is not a folding prop issue. Is there an adjustment I can/should make? I haven't yet got down on my hands and knees to examine the transmission. Anyone know who made the trans and if so, anyone have access to a user's manual? Thanks, and happy 2026!

 

[Loren Beach]

Some more info will be helpful. Being an '88, was it built by Ericson Yachts? What brand and size is the engine? (If a Universal, the trans. is likely a Hurth)

Regards,
Loren

 

[Pete the Cat]

When you go down there, I would recommend that you check the cable and shift lever on the transmission. The transmission lever on most of these must be in the full detent for forward when the lever is full forward. Sometimes the cable clamp can be loose and the shift is just barely getting the thing engaged and you can get intermittent engagement or delayed. You should hope this is it. The other thing it could be is failed disks in the forward position... or something else. Would be helpful to know engine and transmission type. I believe that your boat would come with a 25XP Universal Diesel with a Hurth 50 transmission, but I think there was an option for a Yanmar with a Kanzaki. If it was sailed a lot when left in forward with the engine off you might have some worn disks in either type as both recommend it be left in neutral or reverse when sailing.

 

[Bob Izmirian]

Jane Doe is hull 107, one of the earliest (7th?) in the Ericson production run.
The propulsion is a Universal 18 hp diesel with Martec folding prop.
I don’t think it’s a linkage issue. I just had the motor serviced and transmission oil replaced, hoping that might solve the problem, but not so much. I will double check the linkage just in case. Thanks for the suggestion. I’ve always sailed with the transmission locked in reverse.
The motor and transmission have historically performed flawlessly. I’ve not heard complaints from others about transmission issues on these boats. I was hoping to find some documentation from Ericson about the power train, but at least so far, my web searches have been unavailing.
Thanks for the feedback.
Bob

 

[Frank Langer]

Poor engine alignment can also affect operation of the transmission, and is often overlooked and neglected. But I would check the linkage first, as suggested above.
Frank

 

[Slick470]

Hi Bob. I don't have an answer to your question (we have a Yanmar on our 911) but it's great to see you here. I haven't seen your name pop up since sometime after the old Olson 911 list serve went away and I started the Facebook group. Glad to see you still have Jane Doe!

Lots of Ericson's were built with those Universal Diesels so hope some quality guidance shakes loose for you.

 

[Prairie Schooner]

I have owned Jane Doe, a 1988 produced O911s, since 1992, and raced her extensively on SF Bay. She's now been detuned and I use her for day sailing with a roller furling no.3 and an asymmetrical kite. Recently, I've encountered what I believe are transmission issues. When the gear lever is placed in forward and throttle applied, the transmission doesn't immediately engage, and when it does, it engages with a jolt. It is not a folding prop issue. Is there an adjustment I can/should make? I haven't yet got down on my hands and knees to examine the transmission. Anyone know who made the trans and if so, anyone have access to a user's manual? Thanks, and happy 2026!

Bob,

The clunk makes me wonder if it might be a linkage problem, rather than something inside. However, if that's not the case, with an original Universal it's almost certainly a Hurth. The following link might be a place to start. In post # 43 is a deposit of all the links I'd found helpful. If you're the kind of person who wants to dive deep on how these things work, the video linked in post # 36 is worth a watch.

Hurth Transmission Oil [E35-3]

So I am to be condemned for the fact that we have owned our boat for three seasons, and I have not changed the transmission oil. This is due to two facts: 1. The amount of boat yoga to get to our drain plug is daunting, in fact I am not sure if I can reach it without taking the heat exchanger...

ericsonyachts.org

There will be quite a bit of reading and sifting ahead of you, but I found it worthwhile. Our transmission saga is ongoing. Prior to rebuild or replacement, some people have had very good luck switching to straight 30W oil to eliminate slippage. That would be a next step for us.

Sidebar: Many of us have found it helpful to put basic boat info in our signature line. (If you're viewing the site on a phone, try turning it sideways to see signature lines.) Go to the upper blue bar and click on your screen name. You should see a link for 'signature' where you can add this information.

Good luck,
Jeff

 

[JSM]

When the gear lever is placed in forward and throttle applied, the transmission doesn't immediately engage, and when it does, it engages with a jolt

I had this same issue with a Hurth 50. I was able to nurse it along for a while with fluid changes etc. but it only got worse with time. After extensive research (and almost backing into a brand new Morris M36 ) I spoke with two different marine transmission shops and was told by both that rebuilding was not an option because of low quality rebuild parts.
I installed a Twin Disc MG340 trans along with a new damper plate and motor mounts. The installation was easier than I thought it would be and some vibration issues I was having went away as well.

MG-340/TMC 40 P

The MG-340, also referred to as the Technodrive TMC 40 P marine transmission, is equipped with conical clutches that are mechanically operated and activated by a servo-system.

twindisc.com

 

[Dave G.]

As others have said, linkage should be first on the list. A good way to check is to move the shifter to forward position, then go down below and disconnect the linkage, then see it the lever on the trans is all the way into position. Most of the time the bolt that holds the cable in position on the trans has loosened. Reposition cable and tighten bolt. May have to loosen bolt to reposition the cable correctly. Also you said the fluid was changed so make sure you have the correct fluid too.