Atomic 4...typical cruising RPM????

[Paul]

Hi Guys,Quick question...I have a Cat 30 with an A4 engine. What is your typical cruising rpm?? The reason for my question is that my max RPM I can obtain is 1500rpm?!??! This is all while under load and cruising along. Does not seem right. While at dock and in nuetral, I can easily rev engine well above 1500rpm, but under load only can get 1500rpm max... I don't know if I have bad gas, timing problem, carb problem or if this is just typical for this engine.As always, thanks for your input....Paul

 

[Guest]

1500 not at all typical...

I'm no expert but I do have an A4 in my C27 and you should be able to get hull speed around 22-2600. If I'm not mistaken, max for the engine is supposed to be around 3500, but you will cavitate long before you get there. As to why you are only getting 1500, there could be a multitude of reasons. Fuel, air mixture, dirty carb... And as I said I'm no expert, so I will refer you to a great list where I go to solve my problems with my A4. It's the "atomic4-list@sailnet.net" on sailnet. (sailnet.com) A bunch of knowledgeable guys who can answer just about any question you could come up with.Good luck,Lysle

 

[Rob Rich]

Prop Pitch

Paul, you may have an incompatable prop mated to your A-4, which will not allow it to develop proper RPM. Poor compression, being out of tune, and a host of other things can cause this as well, but I would check your pitch. CDI sells a plastic replacement that is specifically built for the A-4. I have heard good things about it.Lysle is spot-on about sailnet. They have a great list-serv for the A-4. I refer to it all the time, and Moyer's site is invaluable as well. Please let us know what you find!Rob

 

[Paul]

Thanks Guys

Thanks again guys. My first step will be to take the carb off and clean it out. Perhaps the main jet is dirty? I have plenty of RPM while unloaded but limited while under power...I'll post my findings....Paul