Hello. I have a 105hp force( i believe) well, it's a 105hp head w/matching carbs (WB24b's) on a chrysler 125 lower (i think) I know the power head is off of a 105hp and the dual carbs match like I stated. Prop is a michigan Match PR278 (13 1/8x15) which by my calculations is correct for the boat.
The boat itself is a 21ft Bayliner. it's top speed at WOT and 3,000RPMS is around 10MPH.. MAYBE 12. According to the service manual I have i won't see the full HP rating until about 5000rpms. max is 5500. Compression tests on all four cylinder range between 140-150. manual states 145-165 PSI, so I don't see the need to tear apart a head for 5 PSI. Spark Plugs are correct, and are brand new as of yesterday. Underside of boat is clean and spotless as is the prop.
Using the calculator here http://continuouswave.com/cgi-bin/propcalc.pl i determined that at 4500 rpms the motor should be capable of 19.18mph. Thats even with a 3:1 gear ratio(motor could be 2.73 or lower), and plugging in 10% slip. Fuel is brand new, and so are the lines/primer bulb.
My question is this; Why am i only seeing 3000 rpms off of this setup? is the lower unit the wrong lower unit? is it maybe a clogged fuel filter? is it the reeds? any help would be greatly appreciated.
The boat itself is a 21ft Bayliner. it's top speed at WOT and 3,000RPMS is around 10MPH.. MAYBE 12. According to the service manual I have i won't see the full HP rating until about 5000rpms. max is 5500. Compression tests on all four cylinder range between 140-150. manual states 145-165 PSI, so I don't see the need to tear apart a head for 5 PSI. Spark Plugs are correct, and are brand new as of yesterday. Underside of boat is clean and spotless as is the prop.
Using the calculator here http://continuouswave.com/cgi-bin/propcalc.pl i determined that at 4500 rpms the motor should be capable of 19.18mph. Thats even with a 3:1 gear ratio(motor could be 2.73 or lower), and plugging in 10% slip. Fuel is brand new, and so are the lines/primer bulb.
My question is this; Why am i only seeing 3000 rpms off of this setup? is the lower unit the wrong lower unit? is it maybe a clogged fuel filter? is it the reeds? any help would be greatly appreciated.