Thanks John, That is just the information I was looking for. The boat has been rebuilt and was bored and has an RV cam. It get on plane at about 3,000-3400 and will remain up even in a choppy sea at about 25-28 hundred, with out using trim tabs.
On Mar 13, 12:40 am, john hamilton <[email protected]> wrote: > Hi Steve, > > Your cruising RPM is going to depend upon a lot of variables and you haven't > given near enough information to answer the question yet. Assuming your > engine has a stock camshaft, the wide open throttle rpm should be about > 4400-4800 rpm with a full load of fuel and a couple of people aboard, if the > boat is propped correctly. Once the boat is correctly propped, the best > crusing fuel economy will be at the minium speed the boat will maintain a > full plane. That will depend upon displacement, hull shape, propeller > diameter, etc. 3000 rpm is an okay ball park to play in until you make sure > everything is set up correctly. > > 165 degrees is fine for a coolant temperature. If I remember correctly, > Chrysler put 160 degree theormostats in fresh water cooled engines and 140 > degree thermostats in raw water cooled engines. Oil pressure should be at > least ten pounds of pressure per thousand rpm. Engines have the best > longevity if then can stay between 180 and 200 degrees. Lower than that and > they wear rings and bearings a bit faster than they should. Marine engines > often run cool, because they are set up to do okay in the Gulf of Mexico with > 85 degree water and a lot of Uniflite owners in the Pacific North > West are running them in 40 to 60 degree water. > > I have a 27 Express Cruiser with a single Chrysler small block. Before I > rebuilt it, I ran from Petersburg to Juneau (105 nm) at 15 knots. I cruised > at 3400 rpm for about seven and a half hours, maintaining about 45 pounds of > oil pressure and about 145 degrees of coolant temperature on arrival (130 > degrees on departure). That is too cool as far as temperature goes but I run > in cold water and I have a large heat exchanger. I've made this trip several > times with no problems. > > Hope this helps. > > John > > --- On Sun, 3/8/09, steve <[email protected]> wrote: > > From: steve <[email protected]> > Subject: [UnifliteWorld] questions > To: "UnifliteWorld" <[email protected]> > Date: Sunday, March 8, 2009, 10:32 AM > > Hello; > I have recently bought a 1972 Uniflite Salty Pup with a crysler 318 > and direct drive. I was woundering if someone had some advice about a > few basic questions. this is th first gas powered boat that I have > owned. > 1. What should the engine rpms be at an on-plane cruse? what is the > upper range of RPM that you would be comfortable opperating the boat > at for a few hours. > 2. What should the engine temp and oil pressure be at idle Vs cruse > speeds? > Any advice would be very helpful > Steve --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "UnifliteWorld" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/UnifliteWorld?hl=en -~----------~----~----~----~------~----~------~--~---
