Hydromaster 47 cds question

Larry B

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Larry Burrell
If you have one or had one what kind of vacuum pressure did you get with it? I am messing with one now and it's only hitting about 11HG with relief valve tight and plugging the vacuum hose.

Is this normal on this machine? The rpm gauge is showing 2000 rpm so I think it should be much better.


.... while Peeing into the vacuum hose
 
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Ralph Pastorelli
My 03 use to open at 10HG and peak out at 14 so I would say yours is a little out of adjustment.
 
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Lee Stockwell
Pull the hose off the vacuum tank that goes to the blower so you can test just the blower and vac relief. It's common to have a leak you didn't notice.
 

Chris A

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Its been a few years now but I seem to remember my 4.7 running around 2350, is it holding the rpm under load?
 

Larry B

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Chris do you remember what the vacuum pressure was reading at 2350 rpm?

We managed to get it to 13HG today but nothing more than that so i'm not sure if thats just what they run at or not. I would think a 47 would be much better
 

Chris A

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Chris do you remember what the vacuum pressure was reading at 2350 rpm?

We managed to get it to 13HG today but nothing more than that so i'm not sure if thats just what they run at or not. I would think a 47 would be much better


13, I have a 4.8 now and both had the same suck
 

idreadnought

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tank seals on those machines are very weak. If you can only get 11hg when you cap off the hose then a leak is the problem. I have owned a couple of those machines and what I did was go to a wrecking yard and take a seal off of a trunk of a car. I cut the soft part of the seal off and the rest fits the cds nicely. You could also buy a seal from hydramaster but i never wanted to pay that much money. The biggest thing I dont like about hydramasters is the tank seal
 

Larry B

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We have it up to 13HG now with plugging the vac hose. That's with the machine rpm's running at 2500.
Can't help but wonder how much air flow is restricted by the rectangular manifolds that flair to the 3" hoses coming off the blower.


.... while Peeing into the vacuum hose
 

Larry B

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Pigeon Forge, TN
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Larry Burrell
tank seals on those machines are very weak. If you can only get 11hg when you cap off the hose then a leak is the problem. I have owned a couple of those machines and what I did was go to a wrecking yard and take a seal off of a trunk of a car. I cut the soft part of the seal off and the rest fits the cds nicely. You could also buy a seal from hydramaster but i never wanted to pay that much money. The biggest thing I dont like about hydramasters is the tank seal

Do you know what the rpm's were on the machine?


.... while Peeing into the vacuum hose
 

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