SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Ultra460 on May 31, 2009, 09:03:51 AM
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I'm having fuel pressure issues. I installed a new Clay Smith mechanical fuel pump on my BBF and I'm running a holley adjustable fuel pressure regulator with a small russel inline gauge.
I set the pressure to 6.5 psi and after it warms up under the hatch the pressure drops to 3.5-4 psi. I had assumed it was just the gauge because I've had issues with these little inline gauges before and have been running it like this for about a month now. I pulled a couple plugs friday night just to see how things were going and all the plugs looked brand new (white). So I pulled the carb (850 dp) and jetted up. I was running 80's front and rear with no rear power valve. I went up to 82 in the front and 84 in the rear. Took it out saturday and ran it for a while did a full throttle pass and shut down. Pulled plugs and they still look the same. Then I went up to 86 in the rear and it's still the same. I'm starting to think it might be the fuel pump.
Any ideas?
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Have you checked your fuel filter?
Personally, I would probably run a little more fuel pressure, regardless, say 8-9 lbs.
Have you checked both float bowl levels?
You didn't give too many facts to go on, I assume it seems to be running correctly, no loss of power, surging or popping?
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Check floats. you goin out today?
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I've checked and adjusted float bowl levels. The fuel water seperator is brand new. I'm also running a high flow inline fuel filter in between the fuel pump and regulator.
It runs fine it's just the color of the plugs has me worried especially with the hotter weather fast approaching.
I'm thinking about going out today but IDK this problem is buggin me.
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I THINK we're gonna have a boat maintenence day today here. What part of town are you in? Boulder & Lake Mead
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Boat maintenance day?
I'm on 215 and pecos in henderson.
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Boat maintenance day?
I'm on 215 and pecos in henderson.
I think he means My boat may be headed his way, AGAIN, lol. Haven't confirmed this, however.........
Ray
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I think he means My boat may be headed his way, AGAIN, lol. Haven't confirmed this, however.........
Ray
Oh, ok.
I think I'm just gonna try and pick up another gauge first and make sure that's not the issue.
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Ok so I ordered 2 new fuel pressure gauges. I got one to replace the current gauge that's after the regulator and another to install before the regulator. According to Clay Smith incoming fuel presssure from the pump should be 16 psi.
I'll find out this weekend.
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We just had a bunch of boats in my front yard the other day, fixing, adjusting and tuning. Ordered a few pizzas, had a good time.
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We just had a bunch of boats in my front yard the other day, fixing, adjusting and tuning. Ordered a few pizzas, had a good time.
That sounds like a good time. ;D
I hope to find the problem this weekend. I'll try and meet up with you guys if you go out this weekend. I should be out saturday for sure.
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Just thowing out an idea here...
I've had issues with those Holley adjustable fuel pressure regulators, that might be your issue, I've heard they don't hold steady flow...That being said, what if you ran with out it? What's the max pressure that mechanical pump can make? Aren't they usually self regulating? If it's not an incredibly high volume unit, try taking it out of the loop and running with out it to see what happens.
Again, just an idea from things I've heard. I recently had similar issues.
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Just thowing out an idea here...
I've had issues with those Holley adjustable fuel pressure regulators, that might be your issue, I've heard they don't hold steady flow...That being said, what if you ran with out it? What's the max pressure that mechanical pump can make? Aren't they usually self regulating? If it's not an incredibly high volume unit, try taking it out of the loop and running with out it to see what happens.
Again, just an idea from things I've heard. I recently had similar issues.
I don't think I can do that in this situation. The pump is supposed to put out 14psi. I am going to put another gauge before the regulator to make sure the pump is working properly. If it is then it's for sure the regulator.. Should find out this weekend.
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oh ok I see what you mean, yeah 14psi would blow out your needle seats. The regulator is a must in your case. Good luck this weekend.
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So I installed a gauge before the regulator and the pump seems to be the issue. It's only putting out 6psi cold and then drops to about 4-5 after it warms up. I pulled it off and am going to ship it out to clay smith tomorrow.
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I never did make it out today John, the ole lady is out of town, parents are ill. She's comming home tomorrow. I have never lauched and recovered by myself, almost tho the ole lady's got a broken foot. She's in the same air cast I just got out of! Sux to be getting old. Anyway, I run one of those pumps with two dominators, no reg, no gauge, no separater, no problems. I've seen grand national boats running the same exact setup so I figured it must be good. Catch up to you soon....T
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I never did make it out today John, the ole lady is out of town, parents are ill. She's comming home tomorrow. I have never lauched and recovered by myself, almost tho the ole lady's got a broken foot. She's in the same air cast I just got out of! Sux to be getting old. Anyway, I run one of those pumps with two dominators, no reg, no gauge, no separater, no problems. I've seen grand national boats running the same exact setup so I figured it must be good. Catch up to you soon....T
No problem.
Launching the boat alone is a PITA. Plus you have to tie it up to the dock which means you run the risk of someone running into your boat.
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My boat rides kinda "under" the dock, no rub rail. Ya gotta stand there and hold it.
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No problem.
Launching the boat alone is a PITA. Plus you have to tie it up to the dock which means you run the risk of someone running into your boat.
I'm used to launching and loading by myself it freaking sucks!
And I usually have 1 passenger! Oh wait that's all I can fit!
My boat rides kinda "under" the dock, no rub rail. Ya gotta stand there and hold it.
I ride lower then you pal so what does that mean? You gotta hear this boat with the new to me pipes...I'm still deaf!
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You gotta hear this boat with the new to me pipes...I'm still deaf!
New to you pipes..... We need pics :D
I wanna see ;)
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New to you pipes..... We need pics :D
I wanna see ;)
Sorry pal only way your gonna see is on the water!...what are you doing these days since your boat is done?
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Sorry pal only way your gonna see is on the water!...what are you doing these days since your boat is done?
I saw them out the water They look good Nordie ;D
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Sorry for the busted ears Nordie, lol. But I woulda paid good money to see the look on your face when you fired it!
Ray
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Ok so I got a call back from Clay Smith today and he said the pump is good to go. On his bench it put out 21 psi and didn't bleed down after 20 minutes.
He is thinking I have a restriction of some sort. Possibly the rubber fuel line on the suction side of the pump might be collapsing. Or he suggested possibly a clog or restricted vent from the fuel tank.
Any suggestions.
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Sorry for the busted ears Nordie, lol. But I woulda paid good money to see the look on your face when you fired it!
Ray
When I bumped the key and she flaired up...I said whoa look at all them pretty dust colors coming out of the pipes...looked like a rainbow...we know how I like rainbows! Then I said ray is a liar...it does make a difference this fuggin thing is loud...good thing I like loud stuff...imma run it!
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The collapsing hose theory is the first thing I'd look at. Could also be a plugged up pickup, filth in the bottom of the tanks, etc. If your regulating it down on the output side though, would that not limit the vacuum on the inlet side as well? Just thinking out loud, but mechanical pumps mainly push, so maybe too small of feed lines? I dunno, shot in the dark to me. Dunno why you'd need 14PSI EVER ('Cept maybe Terry). Who the one that said there's a difference between High pressure and High volume? Might apply here methinks! I would think a collapsing hose is an indicator of another problem unless the hoses are real soft.
And Nordie, I'd be dissapointed if you baffle them! I'ma keepin mine open, and that is that! Ran it open in front of 6 Deputy Sherrif's and they didn't seem to care, so, lol.
No Steve, Nordie can't post pics right now, his ex-G/F musta gave him the Computer "Clap" as a going away present.
Ray
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My $0.02 is to try replacing all of your fuel lines. I have an open engine boat so some of my visible lines are steel braided but most of it is rubber so it was pretty cheap and easy to replace.
I just tore out all the old dried hose and re-ran fresh new hose in and got to re-route it exactly how I wanted it. I also went from 3/8 hose to 1/2, I realize that may have been overkill but whats the difference, all I really did was give it better flow.
All that being said, it was a fun and cheap project and now I hold 6.7 or 7 psi of fuel pressure all day long.
Give it a try????
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All the hose from the tanks all the way through to the carb is 3/8" ID. I have replaced almost all of it over the last two years there is only very small pieces of old hose between the fuel water seperator and the tank selector switch. I am going to go over it with a fine tooth comb this weekend. Pull all the hoses, verify the vents are working and make sure the pickups are not clogged.
I'll keep you guys posted.
Thanks, John
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Good luck with chasing this issue down...seems to me that something has to be clogged...possibly the pick-up could be clogged...the tank vent could make sense too
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Put a hose in a gas can to your pump and start her up, see what ya get.