This is an ongoing issue with Hurth transmissions. A friend on Cape Cod has had his Hurth transmission replaced twice in the last few years for the same issue you described. Initially, he would start the engine, release the mooring, and end up drifting for a minute or two, until the tranny engaged. Reverse worked fine right from the start. Hurth replaced the tranny, and the new one did the same thing from day one. He used that tranny for the season, since it worked fine once it was warmed up. Last summer, Hurth replaced the tranny again, and as far as I know, it was ok.I have noticed that it is difficult to engage the transmission into forward when it is initially cold, but not reverse. Reverse engages right away. Forward takes a considerable amount of time. I found that if the revs are as low as possible (lower than my normal idle of 1,100 or so rpms) it eventually goes in but the engine is not happy at those low rpms.
However, after the transmission / fluid is warmed up from motoring around, then seems to engage in forward normally.
Any thoughts?
Cheers,
Eeek! That is very likely what started this issue then. That is way too long. When I sailed seasonally I did the trany fluid every spring before launching. Now I do it every 100 hours or 6 months, which ever comes first.It sounds like I am not the only one with this issue unfortunately. I think I will start with changing the transmission fluid (been 5+ years) and see if there is any improvement.
Cheers,
I haven’t played with this yet. I need to do what you did, and manually shift it at the tranny, and see what happens.Any update on your transmission issue?
I am still dealing with the slow forward engagement. Today I ruled out shift cable as a problem. I manually shifted at the transmission (not in the cockpit) and noticed the prop shaft starts to spin, but then after 30 seconds or so, there is a "clunk" and it seems to fully engage and the prop shaft spins much faster.
Do you have the Universal M25-XPB with the Hurth tranny, Paul? My Universal manual calls for 1250 RPM at idle. My 2003 Hurth works fine, shifts right away, doesn't slip. I think the slipping in gear when cold issue with the Hurth trannies is showing up in the newer units.For about 15 years now, I used per the owners note in the my 310 manual...start engine and keep the RPM at 950 to 1,000.
Put the transmission into forward and idle out to break water and by that time everything should be warmed up .....transmission and engine...then increse to desired speed.
Never had a problem.
Some do not wait and increase to 2000 RPM and then the varius transmission stories begin.
My story..... just recently someone else, who wanted to buy my boat, was at the helm of my boat and increased the rpm's to 2450 without waiting and, and, and it sliped out of gear or the prop shaft quit turning .
I mentioned to the captain if you keep the rpm around 1,000 untill you get to the breakwater you will not have this problem.
paulj
Good point, Dave. It makes sense that sailing with the tranny in forward would wear on the plates, etc. The issue about idle RPM's has been discussed several times in this forum. When I bought my boat, the surveyor remarked that 1200 RPM was way too high for idle, and that 900 to 1000 RPM was correct. I did as he suggested and adjusted the idle to 950 RPM. The engine vibrated excessively, to the point the brackets on the heat exchanger broke. I readjusted the idle to 1250 RPM, and the engine idles smoothly, and shifts well, with no issues in 1,700 hours.This issue has been talked about a few times, my 2001 C310 with the same engine/trannie had these symptoms. A transmission rebuild fixed it, the plates were polished and worn out at about 500 hours. I think the PO may have sailed with the transmission in forward.
I start the engine and increase the RPM to about 1250, anything below that and the engine rattles and shakes the whole boat. Before I engage into gear I decrease the RPM to minimum, about 1000 on my boat.
Cheers
dj
Might need to adjust the valves? or possibly check the injectors? it really shouldn't shake as you describe around 1000. are your engine mounts shot? i know mine are and am replacing them this winter with OEM mounts..did as he suggested and adjusted the idle to 950 RPM. The engine vibrated excessively, to the point the brackets on the heat exchanger broke. I readjusted the idle to 1250 RPM, and the engine idles smoothly, and shifts well, with no issues in 1,700 hours.
I think the fact that the M25-XPB is a three cylinder engine has something to do with the idle needing to be higher than other engines.
Not at all. Engine is fine, mounts are good. As I have tried to point out, the Universal manual specifies that idle RPM should be 1250 RPM, and this works fine on my engine.Might need to adjust the valves? or possibly check the injectors? it really shouldn't shake as you describe around 1000. are your engine mounts shot? i know mine are and am replacing them this winter with OEM mounts..
The RPM's on the tachometer on each boat differs alot.
Years ago, I discovered this deference when I was an adventurist.....You use the altenator and a external tach to adjust a more accurte RPM on the boat's tach, one that I could see and verify my self.
My original Hurth 50 trans which came with the boat was rebuilt 2 months ago by Mike Vote and his top drawer trans group....thanks Mike. I took the boat out and did my usual routine and let warm up than took it thru some maneuvers, such that when I got back to the dock, people came up to me and said what was that all about.
Any way no problems.....but I did not take the boat out with new tran and increase the rpm to 2400 when trans was cold, to see what would happen.
Mabe next week
I agree that the tach might not always be accurate. I have checked my RPM's with a hand held tach and calibrated the boat's tach accordingly.
paulj