Bleeding the hydraulic gear system

[Verboaten]

Hopefully the title makes sense.

On our little cruiser, we have an issue finding forward gear, our setup is that the gears are controlled through one hydraulic stick whilst the throttle is controlled with a separate stick next to it.
We can find neutral and reverse easily enough, however finding forward means pumping the stick forward many times before the boat slots into gear.

The previous owner told us that in the past the hydraulic system had leaked leaving him unable to find forward gear, he had topped up the fluid then removed the hose at the engine end, pumped until fluid came out and put it back together when he got forward gear again so I believe the issue to be air in the system.

We are used to bleeding clutches and brakes on motorcycles etc but boats are a new one to us, can anyone advise on how to go about fixing this ourselves or would it be better to have a boat mechanic do this job? The boat has a BMC 1.8 inboard petrol engine if that helps.

Thank you in advance.

[Mutts]

Hopefully the title makes sense.

 

On our little cruiser, we have an issue finding forward gear, our setup is that the gears are controlled through one hydraulic stick whilst the throttle is controlled with a separate stick next to it.

We can find neutral and reverse easily enough, however finding forward means pumping the stick forward many times before the boat slots into gear.

 

The previous owner told us that in the past the hydraulic system had leaked leaving him unable to find forward gear, he had topped up the fluid then removed the hose at the engine end, pumped until fluid came out and put it back together when he got forward gear again so I believe the issue to be air in the system.

 

We are used to bleeding clutches and brakes on motorcycles etc but boats are a new one to us, can anyone advise on how to go about fixing this ourselves or would it be better to have a boat mechanic do this job? The boat has a BMC 1.8 inboard petrol engine if that helps.

 

Thank you in advance.

 

 

 

Probably a leaking seal on the relief valve (pressure side) or a blocked filter near the oil strainer (pressure side also). Your system should be self bleeding. Check the reservoir level.

[Tony Brooks]

"Little cruiser" and Hydraulic gear change system. Unless there is a good reason that it sounds over complicated for a gearbox on a BMC 1.8 petrol. I know Newage/BMC produced a DCC marine gearbox that had a hydraulic clutch but you would recognise teh clutch part and that is a system from the 50s & 60s.

 

Personally I would have the thing out and fit a Morse control with cables.

 

I would recommend that try you loosening the last pipe/hose union before the gearbox and pumping away as you would a clutch or brake system until no more air bubbles flow out with the fluid. Then just hope no air is in the slave cylinder. Have a good look at the cylinder to see if there is a bleed nipple the previous owner did not know about.

 

 

Edited to add: I think Mutts may think that you have a hydraulic drive. I doubt you have a PRV or strainer any more than an automotive clutch system does.

Edited July 5, 2015 by Tony Brooks

[Verboaten]

Thanks guys, we will take a look when we are next down with the boat, not a hydraulic drive I don't think, the boats a circa 1976 23ft Cabin cruiser, I'm not sure of any of the running gear but it works well other than the issue finding forward gear!

[Timleech]

Sounds a bit like the old 'Armstrong' hydraulic controls, which I think were based on the Armstrong lever-type hydraulic shock absorber. I only dimly remember these, all I can suggest is topping up and bleeding as best you can.

 

Tim