Engine Problem

[DAVID SEDORE]

HI. I HAVE A 1985 FOURWINNS LIBERATOR WITH A 350 MAG. WITH A ALPHA 1 . I HAVE REBUILD THE MOTOR TOP TO BOTTOM .IHAVE ALSO REPLACED ALOT OF THE COOLING COMPONETS WATER PUMP, THERMOSTAT,EXHAUST MANIFOLD,IMPELLOR. WHEN WE GO ACROSS THE LAKE WOT AND HAVE TO SLOW DOWN FOR THE NO WAKE ZONE THE STEAM IS COMING OUT THE THRU HULL EXHAUST LIKE I BLOW A HEAD GASKET BUT THE TEMP STAYS WERE IT SHOULD. THE PERFORMENCE IS OKAY. I HAD THE MOTOR ON A DYNO TO MAKE SURE THAT EVERY THING WAS ADJUSTED TO SPEC. THE MOTOR HAD THIS PROBLEM BEFORE I REBUILD THE MOTOR . HELP!!!! I'M AT A LOSS

[Havasu Hangin']

Steam coming from the through-hull exhaust is normal.

[DAVID SEDORE]

thank you for your reply. but the steam can get like you are burning a wet pile of leafs. people will stop and ask if we are okay. i have another question. i would like to get my boat to go faster.i have 14x 19 running 5000 rpms gps at51 mph. is there any hope. i have tried 23 pitch 4000 rpm at 50 mph. i talk to a guy about a boat he had same as mine motor was stock he said he was getting 65 mph+. i asked him what prop he was running al he could tell me was it was a mirge speed prop.thanks again

[Havasu Hangin']

Originally posted by DAVID SEDORE
thank you for your reply. but the steam can get like you are burning a wet pile of leafs. people will stop and ask if we are okay.
The reason steam is generated is from the cold water hitting the heated exhaust. After a run...the exhaust is hottest, and the water is attempting to cool it.
If you had a problem with water flow, the engine will run hot, and the rubber bellows will begin to burn and/or melt. Also, since the manifolds are new, I'm assuming no cracks.
If there is good flow at idle (cold), then you should be fine. The amount of steam will also depend on what type of manifolds. Once again, check for good flow (no restrictions).
Originally posted by DAVID SEDORE
i have another question. i would like to get my boat to go faster.i have 14x 19 running 5000 rpms gps at 51 mph. is there any hope. i have tried 23 pitch 4000 rpm at 50 mph. i talk to a guy about a boat he had same as mine motor was stock he said he was getting 65 mph+. i asked him what prop he was running al he could tell me was it was a mirge speed prop.thanks again
I'm not too familiar with that boat (or how much it weighs), but I'd say you're in the ballpark for a 21' older boat.
You are getting about 13-14% propeller slip (which is OK for a v-hull), but you may be running out of HP. Where did the motor dyno at?
In my (non-expert) opinion, I'd say your gonna need around 450 HP and a prop with some bow lift to carry the nose. If you can get enough HP to spin the 23" prop to 5,000 RPMs (at 12% slip), then I have you at 64MPH.
The guy who was getting 65MPH (with a stock SBC) probably had some magic dust that is not available from most local retailers. Better find out more about his combo.

[DAVID SEDORE]

thanks again i will check my water flow.
my motor dyno at 373 at 5300 rpm and 419 4200 torque . sohow can i get more speed out of it change boats ha.ha.

[Havasu Hangin']

Originally posted by DAVID SEDORE
thanks again i will check my water flow.
my motor dyno at 373 at 5300 rpm and 419 4200 torque . sohow can i get more speed out of it change boats ha.ha.
Change boats? Yep.
In the meantime...try a 21" (stainless) three blade.
Did you dyno the engine with your exhaust manifolds and flame arrestor on?

[DAVID SEDORE]

no i used a car set of headers he uses to test with and no flame arrester.

[Havasu Hangin']

Originally posted by DAVID SEDORE
no i used a car set of headers he uses to test with and no flame arrester.
Then I'm gonna guess you probably have 300-325HP at the prop (using my non-expert expertise).
More HP is gonna be tough without sacraficing the idle a little (which the Alpha won't like), unless you want to tear it apart again and put a stroker kit in.
I guess you could bolt a supercharger on and get 100 HP or so (which the Alpha won't like).
In the meantime, you could upgrade some bolt-on stuff (like exhaust manifolds, carb, intake manifold, flame arrestor, etc.) to make the engine breathe better (if you haven't already), and try the 21" prop.
I bet you'll be around 60MPH (downhill with a tailwind).
Or...the easier way would be to find the magic dust, and ditch the GPS- those things lie too much.