bob's low water pickup has low PSI

**illMATTic** · 08-21-2006, 07:50 AM

i just installed my bob's bigfoot nose cone / low water pickup. it is the single tube design. i did this after getting tips and help from some of you here on S&F. the install went pretty smooth. however, it is only producing 5 psi at max.

it will show 5 psi at idle and then when i give it some gas it drops to 3 then goes back up to 5-6 psi. it would not go higher than that.

this is on a stock merc 2.4. could there be an air pocket in the LU?

any help would be great.

ill

**hsbob** · 08-21-2006, 09:26 AM

my son'd motor has the single LnS unit. the psi you listed is normal for that motor, but after about 2500 to 3000rpm it should start to rise. my son get 10psi plus with the motor almost even with the pad. if you not getting 10 at wot i'd look for some obstruction.

**illMATTic** · 08-21-2006, 10:56 AM

before the install i was getting 5psi at idle and 10-11 psi at WOT. i did make sure there was nothing obstructing the passage before i installed the LU.

the only thing i didnt do is fill the water cavity below the water pump. i only covered the stock water inlets. could this create a void in the fow of water?

**stealthperf** · 08-21-2006, 01:47 PM

I have been following your post and I am very interested in knowing what kind of performance gains you get with the nose cone. I was thinking about getting one myself. Please keep me informed! Thanks dave.

**illMATTic** · 08-21-2006, 01:58 PM

Well Seeing As How I Can Not Take It Over 3000 Rpm Without Risk Of Overheating, You May Be Waiting A While For The Results.

**XSive** · 08-21-2006, 02:15 PM

Do you have any photo's you could post so we can see it?

**illMATTic** · 08-21-2006, 02:51 PM

well i spoke with the guys over at bobs. they are a great bunch of guys over there. they said it was installed correctly per my description. they said i may have cracked the pump housing or the pickup tube on the top of the housing may not be seated properly.

i will have to pull it back apart to check this all out.

**illMATTic** · 08-22-2006, 07:13 AM

i can not find anything wrong with the pump after pulling it all apart and reinstalling it. still no pressure.

is it possable to over tighten the pump housing bolts? i think i may have tweeked the pump housing causing it to lift in the area between the bolts. i noticed the gasket was wet in those areas and dry near the bolts.

**KIRCHNER** · 01-16-2019, 11:00 AM

the fluctuating pressure is probably your poppit valve opening which is normal. once on plane should get 15-20 lbs. IMO

**Merc 2.5** · 01-16-2019, 08:32 PM

10 to 11 lbs is still just tad low to me , r you sure your COMPLETE water pump is gud , housing, everything??, my Bob's single will pump like crazy

**tlwjkw** · 01-16-2019, 10:52 PM

"2006"...………………………...

**delawarerick** · 01-18-2019, 06:39 AM

Just a few years old and a classic

**Will hedrick** · 01-20-2019, 06:10 PM

My ? Is with that motor it sounds like you need a dual tube cone, I have 2 lines on my unit and it gets great pressure, I ran a 1 tube on a 200 vindicator and it done well not sure as you may have a bad water pump either?

**wolfgangb** · 01-24-2019, 05:26 AM

Just noseconed an early (2003) Torquemaster off a 3.0 XS Optimax. At the advice of a friend in the trade had to close off existing cooling water inlets and fill unused water passages with epoxy, otherwise pump could not build pressure.
Wolfgang