blowing hydraulic hoses on mercruiser outdrive cylinders

[rabristol]

I have a 1974 boat with an inline 6 mercruiser (250cid). I have blown 3 hydraulic hoses 2 on the outdrive and one inside hooked to the pump. I know the outdrive (mercruiser 1) does not have any overtravel switches due to the model year.

Is there an adjustment on the pump itself to lower the pressure?

 

[Don S]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Is the reverse lock valve hooked up and working?

 

[Bondo]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Is the reverse lock valve hooked up and working?

Ayuh,..... My guess is it's Working,..... All the time....

 

[achris]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Are you using Merc genuine hoses? The pump can produce about 3,000psi, and the genuine hoses are rated to 5,000. You shouldn't be blowing them even if the reverse lock valve is closed.

 

[Don S]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

You shouldn't be blowing them even if the reverse lock valve is closed.

Tell that to my "Trainee" he blew a hose, replacet it, blew another, then blew the side out of the cylinder. A dime sized hole thru the double tube. Then he ask me why

 

[achris]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Tell that to my "Trainee" he blew a hose, replacet it, blew another, then blew the side out of the cylinder. A dime sized hole thru the double tube. Then he ask me why

I think I'd be saying "What the .....!!!"

How did the pump produce enough pressure to do that sort of damage? If that's the 'norm', then why don't we all blow hoses (and cylinders) when we reach the limit of travel when we trim up? The pump loads up under full load, the hoses and cylinders are being subject to full pressure. I always hear people holding the switch in to 'make sure it's all the way up' at the ramp. Haven't seen a hose blow because of that...

Chris....

 

[Don S]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Hey, it shocked me too
I never expected that kind of pressure out of those old pumps.
Can I explain it, NO. I also can't explain (or figure out) why 41 is the answer to Life, the Universe,and ................. oh, never mind.

 

[achris]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Hey, it shocked me too
I never expected that kind of pressure out of those old pumps.
Can I explain it, NO. I also can't explain (or figure out) why 41 is the answer to Life, the Universe,and ................. oh, never mind.

What could explain it is 'old pump'. If the pressure relief valve (inside the valve body) were to stick, if dirt or debris were to get into the downstream side of the valve, then it could produce enough pressure. It would be VERY unusual, but it could happen.

Chris........

(And it's 42, because that's what you get if you multiply 9 by 6)

 

[JustJason]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

I thought the magic number was 18.....
as in....... hello there... i'm 31.... are you... at least.... 18?

 

[Alumarine]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

I thought the magic number was 18.....
as in....... hello there... i'm 31.... are you... at least.... 18?

Depending on ones age - 41 might be the new 18....

 

[Bondo]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Depending on ones age - 41 might be the new 18....

Ayuh,...

I'd settle for a 41,.....

'ell,.... An 18 would probably Kill me,... It would no doubt Scare me......

 

[cnr2003]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

I have a 1974 boat with an inline 6 mercruiser (250cid). I have blown 3 hydraulic hoses 2 on the outdrive and one inside hooked to the pump. I know the outdrive (mercruiser 1) does not have any overtravel switches due to the model year.

Is there an adjustment on the pump itself to lower the pressure?

I haven't really seen a solid answer yet from anyone on here. I just had the same problem. What should I be checking for?

I have the same engine, just the 1976 model and I just blew a hose today. Stainless steel one nonetheless. It blew off right at the fitting.

 

[Don S]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

I haven't really seen a solid answer yet from anyone on here. I just had the same problem. What should I be checking for?

Did you miss the first reply in this thread? How much more solid do you need?

 

[cnr2003]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Did you miss the first reply in this thread? How much more solid do you need?

Wasn't sure that was the answer. I have no idea what the reverse lock valve is. Can someone expain what I need to check for or am I going to have to go study the manual?

 

[Don S]

Re: blowing hydraulic hoses on mercruiser outdrive cylinders

Start a new thread of your own, and we will be glad to.