SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Vegas on April 01, 2013, 03:43:30 PM
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So in my 19 Hallett bubble deck I seem to only be hitting 2900 rpm or so when on the water. When on the trailer it will rev above 3k (bumping throttle, don't hold this ever) on GPS the boat does 51. Carb was recently cleaned and everything as far as secondaries and throttle linkage. The dizzy is an MSD and has the fast advance springs timing totals around 33° if I remember. Fuel filters are new. Coworker said the fuel line could be bad and sucking shut. Anyone have any further ideas? What should the 460 run in stock form? Thanks!
Lucas
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Well u probly have the same nasty fiberglass tanks as the other Halletts
I'm getting new tanks as we speak ordering new aluminum ones from imco
I changed all lines to larger fuel selector and have two filters didn't help
Mine would bog every once in a while shit hitting the pick up the tiny pickup
How did the fuel system look before u cleaned it I had to look into my tank in the garage with a maglite to see the crap inside
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I was actually about to post in your thread. I have IMCO tanks already, aluminum. Previous owner said they were 10 gal. but I have fit about 12 in them. All my fuel lines are 3/8. I just replaced the line from the pump to my fuel/water separator with some super thick-walled marine stuff but I ran out of it. I just bought some Gates reinforced fuel injection hose to go from the selector valve to the tanks. Also, the lines to the tanks are the only fuel lines that had not been replaced and I have no clue how old they are. I am just trying to get a good list of things to check out before I get to the lake again next weekend.
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How old is the pump and wear ring
If its worn out its like driving a car with a slipping tranny
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It was rebuilt in the 90s and I doubt there is much run time on it since then. My boat is acting in the opposite manner, instead of revving high, it maxes out at 2900 rpm on the water.
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Is the tach correct?
51 mph @ 2900 doesn't add up
Daniel
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I was going to hook up my multimeter and see what numbers it was putting out. The dizzy is new, all new wiring, and new autometer gauge set to 8 cyl. The thing is, I had the boat idling and I hit the throttle and it went above 3k. It also seems as if it has more in it while on the water.
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I had the same problem last summer, turns out i somehow had 2 plug wires in the wrong position. it wouldn't get above 3000 rpms but idled good and ran good. a buddy of mine rechecked the plug wires and found it. after that it ran better than ever!
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I doubt it is the firing order, but I will double check it tomorrow morning. Also, plugs are all brand new gapped at 45
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I had the same problem last summer, turns out i somehow had 2 plug wires in the wrong position. it wouldn't get above 3000 rpms but idled good and ran good. a buddy of mine rechecked the plug wires and found it. after that it ran better than ever!
That's actually one I wouldn't have thought of right off the bat, but does kinda fit.
I'm also in agreement with Daniel that 51 MPH at 2900 RPM is an incredible crazy number!! Tachometer HAS to be jacked up, IMHO. Hearing it run, does it SOUND like 2900 RPM? 2900 RPM is a bit over what most cars cruise at, at say, 75MPH, on the freeway.
Ray
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It does sound like it is spinning more than that, but I can't say for certain. I am going to get the multimeter with the tach adjustment on it tomorrow if I get a chance to run it on the hose. All I know for certain is that when it is on the hose, I can hit the throttle and it goes above 3k without hesitation (And sounds like it), and it feels like it has more revolutions in it under power. Also, from a bit more than 3/4 throttle to WOT there is no rpm difference at this time.
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Do the secondaries open
Are they mech or vacuum
Just making sure u rechecked the fuel and fire
Msd with proper coil. Its not 180 out
What Carb is it is it a new huge arb with stock tiny fuel lines
I'm a Chevy guy but even a blue oval will spin more than that stock
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It's a holley 750, possibly an 850, mostly stock motor. Secondaries open and they are vac. MSD R2R with a blaster SS coil, no balast resistor. I doubt it is 180 out because it doesn't run bad at all, sounds really good actually. I'm gonna check fire order in the morning. I have 3/8" fuel line, it goes:
Tank pick ups to manual selector valve
Selector valve to fuel/water separator (1 week old)
Separator to mech fuel pump with new filter inside
I need to replace the fuel lines from tanks to the selector which I will do tomorrow, have new Gates reinforced fuel injection lines already. Coworker suggested if the lines are old or not the right quality they can suck themselves shut and restrict flow, and that is why all boats have upgraded fuel lines from automotive applications. I won't be able to get it on the water again until sunday though.
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It's a holley 750, possibly an 850, mostly stock motor. Secondaries open and they are vac. MSD R2R with a blaster SS coil, no balast resistor. I doubt it is 180 out because it doesn't run bad at all, sounds really good actually. I'm gonna check fire order in the morning. I have 3/8" fuel line, it goes:
Tank pick ups to manual selector valve
Selector valve to fuel/water separator (1 week old)
Separator to mech fuel pump with new filter inside
I need to replace the fuel lines from tanks to the selector which I will do tomorrow, have new Gates reinforced fuel injection lines already. Coworker suggested if the lines are old or not the right quality they can suck themselves shut and restrict flow, and that is why all boats have upgraded fuel lines from automotive applications. I won't be able to get it on the water again until sunday though.
If it was 180* out you would know it. A couple plug wires in the wrong place, that's one I wouldn't have thought of, but worth a check. Seen that on U-Haul trucks in the past.
I'm going with the concensus that the tach is snafu. Or it's incompatible/not set up correctly with your ignition, something. 51 MPH out of a pretty heavy 19' Hallett does not equate to 2900 rpm on a stock 320 HP engine. Just not buying into that.
Also, on the hose, remember you are not loading the motor. A Jet Drive, IN the water, acts, for the most part, the same way a dynamometer does to measure crankshaft HP. The jet drive, for the most part. (I know, some of us are hitting them with 6-7-800 HP and a few well beyond that, but that is an entirely different matter). The motor is gonna quit before the jet drive does, if the jet is in decent shape. More RPM, more resistance to the engine at an exponential rate. This is why you can almost look at a Berkeley Impeller chart and find your impeller, and your max RPM, and be pretty darn close to what a dyno would tell you your max HP is AT that RPM.
A standard, marine 460 is a 320 HP deal, and usually an A impeller in the pump SHOULD let you spin up to 4600 or so RPM. My old 21' Biesemeyer had a fairly fresh, new, Harmin Marine 460 and JC-A and would spin to 48-4900 with no problem. A whopping 50 MPH.........Mind you....... Only mod was an 800 CFM carb.
I'm not saying your boat is as heavy as that old tank was, but if you're pulling 51 MPH at 2900 basically stock, we are ALL doing something WRONG!
Running the boat on the hose, you are only trying to cool the motor, and hopefully you're stuffing a hose both up the intake and up the wazoo to lubricate the pump while doing this! What is going to happen doing that is the motor is free-wheeling and will spin up to whichever gives up first, the ignition or the valvesprings. Means nothing about where the power is, or where the problem may lie. Particularly with a Vac Sec'y carb (Which I am in the minority of being a fan of).
Keep these things in mind playing with this thing. ;)
Ray
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Stick a gauge before the Carb to see if u have six PSI going to the Carb under load
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I was just trying to keep it simple
Even if the tach was wrong ur GPS should show u some more speed. Tach wrong or not not ur issue keep on the fire and fuel path till u know neither one are wrong
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I will hook up my multimeter tomorrow to verify the actual rpm's. Does 51 mph seem like a good number though? I remember I hit 55 once with 3 people and my Bimini up with a different carb and a non working tach. I always spray another hosein the jet outlet when it is on the trailer. I have also tried all the different tach settings I have and they all show less than it does on 8 cyl. I have been working on this boat a while and I just want everything absolutely perfect. I appreciate the thoughtful responses
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Same ignition just different Carb before???
55 with a loaded boat probly not too far off there
Why did u change carbs
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Although I had a 20 foot Tahiti minday and had a stock 454 iron manifold and all only thing I had was a 750dp and loaded down 4 peeps icechest ski ropes jackets anchor she ran 56 on GPS and that thing had a Panther jet.
Even bone stock u should be mid 50
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Although I had a 20 foot Tahiti minday and had a stock 454 iron manifold and all only thing I had was a 750dp and loaded down 4 peeps icechest ski ropes jackets anchor she ran 56 on GPS and that thing had a Panther jet.
Even bone stock u should be mid 50
His Hallett I would liken to my Charger. VERY heavy, well laid up boat! I can almost taste 60, consistently (It's done 67 downriver......with a tailwind.......) with my Charger now that it has an energized YJ, Diverter with a mild 455. But that is a lot of pump work to make that happen.
In Vegas's case, he has a pump/engine combo rebuilt maybe, what, 30 years ago?
No, 51 is a very respectable number, and enjoyable! Obviously, some tired hardware there, IMHO.
The "non-working tach" comment caught my eye though. Is this the SAME tach?
Ray
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The tach I had before was inop. I bought a new set of gauges and re-ran the entire boat wiring at that time. I swapped the old 750 edelbrock off the motorbecause it made it so my tow hook would not fit, and this holley was built by a guy in pahrump who used ot build Richard Petty's carburators. This was bought from a good friend who also sold me fresh reworked heads that were redone by John Force's machinist. When I had the heads off, the pistons were extremely clean, and the cylinder walls were immaculate. I ran a cold, dry compression test and the numbers were all around 125 average. The farthest difference was 123 on one and 130 on another. It just feels like it has more. I am really leaning towards the fuel line, but I won't know for sure until I can get her on the water. 12JC with NO place diverter
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Check the back of tach to make sure it is set on 8 clyinders not 4 or 6 cylinders. if its not missing or anything the motor, could be that tach.
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I was just trying to keep it simple
Even if the tach was wrong ur GPS should show u some more speed. Tach wrong or not not ur issue keep on the fire and fuel path till u know neither one are wrong
I agree with Ray :screwy:
My Saguaro, rigged w/ 460 ford, stock, logs and snails- 52 mph (previous owner)
Now with an L31 SBC, 55 loaded (@~4600), gps'd, closer to 60 by myself.
A 2BBL 454 pulled 4400 on an 'A' Impeller, mid 50's, @ Silverwood
A 460 stock, 51 is decent, a good tune may get a mile or 3 out of it, then its cubic dollars. ;)
Thats all I got
Daniel
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Sorry what I meant was keep looking if the motor is done revving at 3000 grand watchingtach or not if it runs flat while u have throttle left sounds funny.
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Yeah, sometimes the rpms will begin to drop if I am holding it at WOT as well, and if I back off on the foot pedal, it will jump back up. Carb is adjusted well, I am about to double check my firing order and timing. I just figured I should be able to do 55 with myself in the boat with no bimini on flat water. I think I am going to wait until I can get some USCG approved marine fuel hose to install the new pickup lines, but I will pull the old ones off once I am done running it to see how they look.
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Hey I have the same issue I have a 73 biesemeyer 22.6ft cruiser and i know its a heavy b!tch but in the water I can only get the boat up to 3000rpm an running about 40mph with bimini up. Out of the water I can get it way past 3000 the motor is a 455 with about 35 hrs on a rebuild but unsure of the mantaince. jet is a 12 jc berkley. I have a 8867 1406 weber 4 barrel unsure of the cfm but but I think 650?
Sent from my SGH-T999 using SoCalJetBoats mobile app
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May be a fuel delivery issue, what fuel pump you running
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Yes Holley needs at least 6 psi
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If that was towards me I have no clue lol just got the boat last season I will check on it tonight
Sent from my SGH-T999 using SoCalJetBoats mobile app
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So I hooked up the tach attachment on the multimeter and when I am at 2900 rpms the tach is off because I am hitting around 4200 rpm. I installed the new fuel lines so hopefully when I get to the water I can get a few more rpms. I will also see if I can check my fuel pressure coming out of the pump and see what it is at. I want 55!!! I appreciate all the input people. I am going to double check the output specs of the dizzy and maybe resend the tach back to autometer for a replacement.
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Sweet now hopefully u have that 6 PS I of fuel going to that Holley
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Yeah hopefully I get some time tomorrow to check it out. Does anyone have any suggestions for which timing springs to use in my MSD? I have the fast ones in now, thinking about going for the middle ones to see if it makes any more difference for cruising speeds.
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If ur on it and it starts to lose power sounds like a fuel delivery prob pump not keepin up or the floats not adjusted or needle and seat not opening all the way for what ever reason
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So I checked today, and I have 6 psi coming out of the pump when I disocnnect the ignition and crank it. I decided to pull the stone filter off of y carb, and there was little pieces of stuff that almost looked like sand in it, I think it came from corrosion inside my stainless braided line form the pump to the carb. I hit it all out and ran some carb cleaner and an air hose through the line. Maybe that was my problem, it wasn't allowing full fuel flow at WOT. opinions?
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Could be run it and see hook up a pressure guage abd have some one watch it while ur running
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Haha i did this last year with my boat! I only hit 3000 with my 460 and could not figure out why!? Its just your tach, its on the wrong setting.. now im at around 4500 r's. Chech the back of your tach (: