Chrysler 20HP prop question.

[i386]

I have a 202HD s/n 2043 (I have this memorized now)<br /><br />I have noticed when I'm in the boat by myself (less weight) that after the boat planes out I can back off the throttle a little because the extra rpms are not contributing to any more speed. If it was a car I'd say my wheels were spinning.<br /><br />If there's another person in the boat with me I have to keep it wide open to stay on plane.<br /><br />Could I squeeze a little more speed out by using a different prop when it's just me in the boat? Even if it took a little longer to plane out it might be worth it.

 

[WillyBWright]

Re: Chrysler 20HP prop question.

I doubt you'd get more than another mph or two. But it never hurts to have two props in case one gets damaged. So I guess the answer is probably yes. But there is a point where too much pitch is too hard on the motor and you actually lose speed.

 

[rbruce63]

Re: Chrysler 20HP prop question.

The answer to this equation is in the actual rpms that you are achieving with the boat fully laden. If you are in the recommended rpm range of 4,500 to 5,500 you have the correct pitch and diameter. Increase the pitch 1" and you will reduce the rpm's 500 rpms. Increase the diameter 1" and you will reduce rpm's by 1,000 rpm's. <br /><br />But in your Chrysler 20 the maximum propeller diameter is 8 1/2". Propellers for this motor are difficult to find but perhaps you will find an 8 1/2" X 12 1/2" such as the one that came on the Chrysler 25 and this will work to your advantage if you are running past 6,000 with the boat fully laden.<br /><br />Also the conditions of the climate and the barometric pressure influence the performance of your motor, so adjusting the mixture screw also helps.

 

[i386]

Re: Chrysler 20HP prop question.

I've noticed that when it's cooler outside it seems to have a little less power, not to mention it's hard to start. Actually, it takes about 4 or 5 pulls to start cold. When the temp drops to below 60 degrees it takes about 10-15 pulls to start when the motor's cold.<br /><br />I keep a spare prop but it's the same as the one on the motor.<br /><br />Just about everything for this motor is hard to find. I think I'll just leave it the way it is and concentrate more on catching fish rather than trying to tweak out an extra mph or two. Thanks.

 

[rbruce63]

Re: Chrysler 20HP prop question.

Barometric pressure is also influenced by the temperature of the air. If it's cold outside you should adjust the idle mixture screw to make use of the increased weight of the air and the increased displacement of your engine. Yes, it's hard to start and you should conveniently use your choke to start the motor. <br /><br />Have you tried raising the motor a bit? The motor's antiventilation plate should be level with the bottom of the transom of the boat, however, you could rise the motor by placing a hard wood spacer between the clamps and the transom raising the antiventilation plate 1" or 2" above the bottom of the hull. You will get increased revolutions per minute quicker.<br /><br />How's fishing in the cold? What species are you after?

 

[i386]

Re: Chrysler 20HP prop question.

I think among fishermen on this forum, cold is a relative term. I'm mostly fishing for largemouth bass. Occasionally we'll get a hybrid. I hear the cold weather has really gotten the crappie turned on, but I've never fished for them.<br /><br />Even on a nice day, the motor can be a chore to start and I do use the choke. I might look into raising the motor an inch or so.

 

[rbruce63]

Re: Chrysler 20HP prop question.

i386: Always use the choke to start a cold engine, when the motor starts to pick up you can depress the choke back to its normal position and let the motor warm up. But if you try to start the motor cold without the choke it's going to be mighty hard to do so.<br /><br />Can you eat largemouth bass? largemouth bass and crappies are temperate water species for us. We have other species in our lakes and most are eddible, but I do not know their names in english.<br /><br />I'm heading to the channels in the Caribbean of Costa Rica next weekend. Had my 20 started after the third pull, our weather is in the upper 70's and humidity is only 68%. What else can you ask: That Snook and Calva bite. Perhaps a nice Tarpon too, but these are difficult to fish and you have to get deep into the river bars which are dangerous.<br /><br />What brand of oil are you using and what type of gasoline are you running in your motor? Remember to use regular unleaded as prescribed by the owner's manual. As far as oil is concerned I rather use a private brand such as Mercury Premium or Bombardier XD-30 on my motor.

 

[rbruce63]

Re: Chrysler 20HP prop question.

i386: No luck fishing, great boat ride, lots of birds, sea otters, no sights of manatees although the area is for the conservancy of these species. <br /><br />The motor's idle mixture was thrown off by the altitude difference between San José and the Caribbean. <br /><br />It was hard to start the motor when hot or after stopping but it was happy at 7/8 throttle.<br /><br />I will check carburetor, points setting and then decide if it is time to sleeve back and overhaul as mine has #2 piston scratched and with 95 psi compression.