Re: Prop issue??
Jeff, Thank you for the bump and here are the answers so far....
No 600 pound passengers, and the TACH is almost dead on accurate. We used a digital timing light, to verify the tach.
I did talk, kinda poked and prodded a few questions, to the engine builder. I feel wrong to accuse him of any inproper actions. He still claims that the motor was built to a 300HP rating, and I can't argue with him. He has built several engines for me in both gas and diesel and they have performed as expected if not exceeded expectations. He is also a long time accuaintence of the family who has kept his company busy by word of mouth referrals alone. I do not have a spec sheet not do I know which engine kit he installed. I did hear the rumor that a CRANE cam for a 300 HP marine application is worthless, but I have no idea if that was the brand of cam installed. I am starting to think that it might be time to look into a different cam. I just wish I had the time and $$$ to drag the boat 300 miles south to take it to the lake where we have run it for the last 14 years where the base line was produced from years of use.
QC,
I did stop. I feel like I have been chasing a ghost with this. Sand Hollow Lake's (in Utah) elevation is almost 3000' above sea level, and Utah Lake's is 4551' above sea level. The carb has not been re-jetted. We rebuilt the carb when we were chasing this ghost problem and noticed that the motor was running extremely rich, and the fuel puddling up in places that fuel was not supposed to be was a dead give away too.
We have looked into valve adjustment and reverified that they are in perfect adjustment. Im sorry I didn't post that a few posts ago. We first set them with the motor at TDC and then spun it around once to adjust the remainder valves. Then it was reverified with the motor running just to make sure everything was properly adjusted. Valves are not the issue. We are thinking that the cam may be the overall culpret, I just dont wan't to face that reality of having to pull the motor back out and tear it down to replace the cam.
If the rebuild kit was mislabled, I have no idea if the whole kit was or if it was just a single part of the kit. There are way too many varibles that could easily drop HP in a motor kit.
I did not drop down to a 15* prop either. Thought about it, and ruled it out once I sat down and thought about it.
Sorry everyone that I have been offline for the last week, I am Active Duty Army and they keep me rather busy.
HWSIII,
My outdrive is a Merc Alpha1 GEN II is geared to 1.50 to 1. Would a elevation of about 1500' ( from 3000' to 4550') make this kind of performance change? Could elevation really be the whole culpret?
Like I posted in a post earlier, most of my friends are in 26' to 28' Cuddy/Aft Cabs turning 5.7L to Bravo/Volvo outdrives and they are turning closer to 4900+ rpms at WOT. Its sad when your friends mini yachts can blow past you doing 45-50mph when they have 260HP engines.
Thank you for all the help so far. I am still stumped.....