michael950
for me to POOP on!
- Location
- Houston, TX
Major props to Prem1x for this info.
Christian has an MRD mechanical fuel injection system on his blaster, check out his build thread. Sweet ski. Prem1x's yellow B1 resto
For MRD Mechanical Fuel Injection:
Replacement parts, instructions doc: PWCT: MRD Injection Check Valves
Contact info: MRD Racing - Dave Berryman
For easier starting: PWCT: MRD injection
Be careful of water injestion: PWCT: 50mm Fuel Injection By MRD Yamaha 62t
Critical fuel pump: MRD-Fuel-Injection-Yamaha-701-760
Check valve can pop off: Anyone with MRD skillz coming to the Ride?
Fuel pump gear: PWCT: MRD fuel injection fuel pump or nylon gear for the fuel pump
Use tank foam: MRD Fuel Injection
Harry Klemm's thoughts off GroupK.com http://www.groupk.com/archpwc97.htm
FUEL INJECTION - In the later 1990's many new watercraft engines may be built with fuel injection systems in an effort to comply with forthcoming EPA standards that will be mandated for all recreational watercraft. The high performance aftermarket injection systems available today fall into two categories, electronic and mechanical. The electronic systems we have seen, besides being terribly expensive, lack so many fundamental safety features, we consider them to be unsafe for any application. Of the safer mechanical type, the best developed system is probably the one offered by MRD. This MRD system, though very expensive, (about $1100.) can be a worthwhile value to the "unlimited budget" professional racer. However, it's questionable whether the long term durability and the difficulty of tuning is suitable for even professional racing applications. Many pro racers have recently abandoned fuel injection.
http://www.groupk.com/tec-carbs99.htm
Mechanical Fuel Injection - Within the pwc community, the only aftermarket fuel injection system that has stood the test of time is the one offered by MRD. This mechanical injection system has an advantage over all carburetors in the sense that it does not depend on "carb signal" to conduct it’s metering work. Hence, MRD owners can use huge venturi throat diameters with little concern of harming "single point" metering. Single point metering refers to the amount of fuel being delivered at one particular load level, and one particular rpm. The MRD fuel delivery curve is strictly rpm based (driven by a fuel pump at the crankshaft), and allows the owner to make various range adjustments via a series of adjuster screws and pop off valves. Many pwc owners (grudge racers in particular) have had very good peak speed results with this fuel management system on many different engine platforms.
Unfortunately, all this simplicity comes with a few important compromises. The first, and foremost, is that the MRD system has absolutely no ability to deliver less fuel to an unloaded (out of the water) engine that is offering a weaker signal. The result of this inability to self-adjust (as all conventional carbs do) is a very noticeable over-rich condition when operated on rough water conditions. This same phenomenon contributes to the MRD's very high rate of total fuel consumption (higher than virtually any conventional design carburetor). On the water, this inability to correct fuel metering for unloaded operation can lead to a "landing with the brakes on" feeling as you run through rough water with high throttle openings. MRD owners, who ride on rough water, are forced to make a compromise of the mixture that might be ideal on glass vs a mixture that does not foul the plugs during unloaded operation. With such a compromise setting, the risk of detonation, or piston scori ng, is greatly increased if you suddenly find a big piece of glass water. Furthermore, mechanical fuel injection will not correct for varying air density conditions (as a strong signal carburetor can).
All this said, the MRD system can work well so long as you are willing to regularly fine tune it for any changes in the prevailing water and weather conditions that you will be riding in. While the MRD system has little in the way of self compensating abilities for mid range operation, it "can" be easily tuned to meter the correct amount of mixture for full throttle smooth water operation (this is called "single point" operation). Because of it’s ability to work very well under single point operation, the MRD systems have been successfully used by many grudge racers who ride only on smooth water conditions (where no compensating abilities are ever required).
From our perspective, this system can work well for individuals that operate on glass water conditions in areas that do not experience significant swings in air temperature or air density. While this might be fine for some owners, most of the high performance pwc owners we deal with are seeking a fuel management system that is more versatile, and more forgiving to adjustment.
Christian has an MRD mechanical fuel injection system on his blaster, check out his build thread. Sweet ski. Prem1x's yellow B1 resto
For MRD Mechanical Fuel Injection:
Replacement parts, instructions doc: PWCT: MRD Injection Check Valves
Contact info: MRD Racing - Dave Berryman
For easier starting: PWCT: MRD injection
Be careful of water injestion: PWCT: 50mm Fuel Injection By MRD Yamaha 62t
Critical fuel pump: MRD-Fuel-Injection-Yamaha-701-760
Check valve can pop off: Anyone with MRD skillz coming to the Ride?
Fuel pump gear: PWCT: MRD fuel injection fuel pump or nylon gear for the fuel pump
Use tank foam: MRD Fuel Injection
Harry Klemm's thoughts off GroupK.com http://www.groupk.com/archpwc97.htm
FUEL INJECTION - In the later 1990's many new watercraft engines may be built with fuel injection systems in an effort to comply with forthcoming EPA standards that will be mandated for all recreational watercraft. The high performance aftermarket injection systems available today fall into two categories, electronic and mechanical. The electronic systems we have seen, besides being terribly expensive, lack so many fundamental safety features, we consider them to be unsafe for any application. Of the safer mechanical type, the best developed system is probably the one offered by MRD. This MRD system, though very expensive, (about $1100.) can be a worthwhile value to the "unlimited budget" professional racer. However, it's questionable whether the long term durability and the difficulty of tuning is suitable for even professional racing applications. Many pro racers have recently abandoned fuel injection.
http://www.groupk.com/tec-carbs99.htm
Mechanical Fuel Injection - Within the pwc community, the only aftermarket fuel injection system that has stood the test of time is the one offered by MRD. This mechanical injection system has an advantage over all carburetors in the sense that it does not depend on "carb signal" to conduct it’s metering work. Hence, MRD owners can use huge venturi throat diameters with little concern of harming "single point" metering. Single point metering refers to the amount of fuel being delivered at one particular load level, and one particular rpm. The MRD fuel delivery curve is strictly rpm based (driven by a fuel pump at the crankshaft), and allows the owner to make various range adjustments via a series of adjuster screws and pop off valves. Many pwc owners (grudge racers in particular) have had very good peak speed results with this fuel management system on many different engine platforms.
Unfortunately, all this simplicity comes with a few important compromises. The first, and foremost, is that the MRD system has absolutely no ability to deliver less fuel to an unloaded (out of the water) engine that is offering a weaker signal. The result of this inability to self-adjust (as all conventional carbs do) is a very noticeable over-rich condition when operated on rough water conditions. This same phenomenon contributes to the MRD's very high rate of total fuel consumption (higher than virtually any conventional design carburetor). On the water, this inability to correct fuel metering for unloaded operation can lead to a "landing with the brakes on" feeling as you run through rough water with high throttle openings. MRD owners, who ride on rough water, are forced to make a compromise of the mixture that might be ideal on glass vs a mixture that does not foul the plugs during unloaded operation. With such a compromise setting, the risk of detonation, or piston scori ng, is greatly increased if you suddenly find a big piece of glass water. Furthermore, mechanical fuel injection will not correct for varying air density conditions (as a strong signal carburetor can).
All this said, the MRD system can work well so long as you are willing to regularly fine tune it for any changes in the prevailing water and weather conditions that you will be riding in. While the MRD system has little in the way of self compensating abilities for mid range operation, it "can" be easily tuned to meter the correct amount of mixture for full throttle smooth water operation (this is called "single point" operation). Because of it’s ability to work very well under single point operation, the MRD systems have been successfully used by many grudge racers who ride only on smooth water conditions (where no compensating abilities are ever required).
From our perspective, this system can work well for individuals that operate on glass water conditions in areas that do not experience significant swings in air temperature or air density. While this might be fine for some owners, most of the high performance pwc owners we deal with are seeking a fuel management system that is more versatile, and more forgiving to adjustment.
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