Need help with Prop. size-Problem Solved--

[ramster]

Re: Need help with Prop. size

Re: Need help with Prop. size

sorry duplicate

 

[fabrimacator21]

Re: Need help with Prop. size

Re: Need help with Prop. size

I agree... that motor shouldn't have any problems spinning a 21 pitch prop... should be up around 5k. I'd start checking your points, carb, fuel filter, throttle linkage(make sure your getting full throttle), etc.

I've been playing with a lot of cams on that program and typically the car/truck cams make more hp and tq all the way through the rpm band. The marine cams typically top out at 5k but make less power then the auto cams at 5k. The only difference I've noticed is where the auto cams make peak power at a higher rpm (which is typically too many rpm for a I/O at 5k+) but still make better power then the marine cams all the way through the rpm range.

 

[hwsiii]

Re: Need help with Prop. size

Re: Need help with Prop. size

Error

 

[captainloud]

Re: Need help with Prop. size

Re: Need help with Prop. size

Ramster, why don't you back out of your garage with your engine cover up again. How much water do you have under that ripped vinyl now? I bet almost as much as that Ravens got in its hull.......................

Why not put the Raven on the local truck stop scale and see how much she weighs? I remember pulling like 600-800lbs of wet floatation foam out of the hull of my bayliner in ramsters garage a few years back. I hope ramster comes across another 200lbs trash bag of the stuff.

Look its either lack of power which you say you have plenty of or a very heavy boat. So which one is it?

 

[ringmaster72]

Re: Need help with Prop. size

Re: Need help with Prop. size

I finally had a chance to take a look at the boat. I pulled the flame arrestor off and it looks like the back 2 barrels have not been working. I have always suspected this, but never got around to testing it because it was running so good. It is a Holley spreadbore and the front two barrels have a "film" from the gas and the back two "larger" barrels are clean as a whistle. So, this leads me to believe that they have not been opening.

It is a vacum secondary, so it is my understanding that the back two will not open up until the engine is under a load, so I will have to check it while on the water as it will not be enough on the muffs. Is this correct?

 

[fabrimacator21]

Re: Need help with Prop. size

Re: Need help with Prop. size

The back two larger barrels are gonna be cleaner since they aren't used as often as the smaller ones...

Vacuum secondaries should come in at a certain rpm (whatever the rpm is where enough vacuum is being pulled). Load or no load. However DON'T do it on the muffs. It's gonna take some revving to see if they're opening which you shouldn't do on the muffs(not enough water to the pump).

If they really aren't engaging then your running VERY lean at WOT and you should be able to tell by pulling a spark plug. If the plug is white and chalky your lean which probably means your secondaries aren't kicking in.

 

[ringmaster72]

Re: Need help with Prop. size

Re: Need help with Prop. size

I really think that they are too clean, but the only way to know for sure is to get out on the water. Im just going to have to take my hatch off and watch the carb while somebody drives. I am going to try as soon as I can get on the water.

 

[fabrimacator21]

Re: Need help with Prop. size

Re: Need help with Prop. size

I really think that they are too clean, but the only way to know for sure is to get out on the water. Im just going to have to take my hatch off and watch the carb while somebody drives. I am going to try as soon as I can get on the water.

Have a fire extinguisher handy and keep your face clear... not hard for that thing to backfire out the carb and cause an explosion or fire when the spark arrestor is off.

 

[ringmaster72]

Re: Need help with Prop. size-UPDATED 7/13/09

Re: Need help with Prop. size-UPDATED 7/13/09

I just took it out to see what the carb secondaries were doing and they were not working. I took the hatch off and had a friend drive so I could see what was going on and they did not move at all. So, I let him get the boat up tp 55mph at like 4400rpm, which is the most it will do. Then I manually kicked the secondaries open and it took off. It went up over 60 mph and over 5000 rpm without fine tuning the trim or anything.

So, it looks like I am good to go, I just need to get the vacum secondaries working. Im going to order a vacum diaphragm kit and get the spring kit and see what I can get done.

Tim

 

[MikDee]

Re: Need help with Prop. size-UPDATED 7/13/09

Re: Need help with Prop. size-UPDATED 7/13/09

Ha, ha, ha, Great! Well Good for You! You better get the right prop on there now to tame that puppy down!