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When you guys have the motor dynoed, this might be a dumb question, but, is the motor in the boat. I could pull the motor and have it dynoed but I would have to pull the fuel system and ignition for an accurate tune. If not there would be too many variables once the motor is back in the boat. There is nobody in the area that I know of with a propshaft dyno big enough.
Thanks for the input Jason |
Where are all the veriables? Use the same ign system and fuel system from the boat.
The only veriable is the exhaust if you don't use your exhaust. Prop shaft dynos do exsist. |
Originally Posted by Warlock28SXT
(Post 2524539)
The motor will only turn 42-4300 RPM's I have all -10 line feeding the stock fuel rail/injectors and -8 return. If I knew how to post pics I could show what I have done. I tried going to a 28" bravo 1 from my 30" just lost about 5MPH same RPM. Could/is the factory fuel rail be to restricktive? A number of things can keep you from turning the RPM's. How does engine run up to 4300? In my boat after installed, I could rip the prop loose while on plane around 2500 rpm, motor would rap to 4500 & not go any further. After much work, turned out problem was MSD box. Changed out box & motor would then run up to 6,000. If this is new setup problem could be cam, exhaust, heads, or ?? |
The boat comes out of the hole a bit slow 1.36 gears and 30" bravo 4 blade(stock). Midrange is pretty strong. The boat accells pretty hard then nothin. From about 3/4 throttle to WOT the motor does nothing more. I will have to look up all the motor specs to give a more clear pic as to what I have going on. I can tell you this, the motor was rebuilt after a valve seat dropped #8 now it is .030 over SRP pistons BRODIX heads new cam the smallest pulley they make for the M1. All new fuel sys. cartech FMU and stock ignition. I'll get the details of the cam dur lobe sep etc. along with piston info.
Thanks for the reply Jason |
Crank it up, pull the throttle back and turn the key off, check the plugs. If everything looks good, you might want to try a smaller prop.
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Originally Posted by Warlock28SXT
(Post 2524539)
Thanks for the reply Griswald.
I have since bought and installed the Cartech FMU. It is installed on the return side of the fuel rail then to the gas tanks. It appears to be working correctly. After fisrt install I made a pass the motor sounded like it was super fat. I tune the FMU per the instructions. It runs ok now but...... The motor will only turn 42-4300 RPM's I have all -10 line feeding the stock fuel rail/injectors and -8 return. If I knew how to post pics I could show what I have done. I tried going to a 28" bravo 1 from my 30" just lost about 5MPH same RPM. Could/is the factory fuel rail be to restricktive? Also I am only running about 150 deg motor temp. Is this too low a temp to get out of cold start mode, or is the motor just starving for air. The weather is starting to break here in MIL WI. and wanted to get this straigtened out. any furht help would be very helpfull. Jason p.s. Still the same guy as the old posts just went through some changes and had to re-register I went up to BBlades and tried a 28" stock Bravo 1 see above |
Does your fuel pressure rise and stay constant throughout the run?
Maybe your fuel plumbing is the issue. I run my main fuel line to an SX regulator then take the return from that to the FMU. The output of the FMU returns back to a T fitting at the inlet of the fuel pump. |
Not trying to hijack this thread, but I am in the middle of tuning a (kinda) similar setup. Maybe we can help each other...
My problem seems to be too much fuel. I am running a spanking new 454MAG with Procharger M1-sc. I have plumbed sx pump through two regulators like some others on this board. I have installed innovate afr meter, and had Crockett re-map ecu. I have had to back regulator completely out (25 psi) to even be able to get on plane, and am still running 10.8-11.2 or so AFR at midrange rpm. I have had to unplug the boost reference on both regulators to even get past 3000 rpm due to going over rich and bogging down. I am thinking the ECU is programmed to fat (maybe duty cycle or something) … What do you guys think? |
Any idea what your timing advance is at mid-range and WOT?
My base fuel pressure is 42psi and I'm around 13.2 at idle. 11.2 at your midrange seems a bit rich. A couple degrees timing can make a world of difference. |
Originally Posted by Griswald
(Post 2525552)
Any idea what your timing advance is at mid-range and WOT?
My base fuel pressure is 42psi and I'm around 13.2 at idle. 11.2 at your midrange seems a bit rich. A couple degrees timing can make a world of difference. |
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