LMAO--maybe he was doing that math we've discussed in another thread recently
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Ok my 2 bits worth. I do not know about the 12's but the 892 and the 692 i have a masters degree in
this kind or crap. The guys are correct start with engines anything can be a issue from peeing injector to
low compression and so forth. I fought the problem in both my 45c and my 52c. I was almost ready to take out pitch to gain the
RPM"S. I was didcussing the problem with a very well known DD mechanic of about 20 years and X factory DD school teacher.
He suggested test at NO LOAD meaning at the dock wide open to see if they would turn up. If the turn up at no load most likely you have a prop problem.
I am not saying turn those 12 wide open at no load i do not know. But i have turned the 6 and 8's wide open at the dock with no load.
With the 8's i found out i had a injector problem had several that were peeing not spraying.
Maybe some one else will chime in and kill this line of thought. When i say wide open I mean on the pends for just a few seconds. I know what you thinking
this guy crazy. How ever it is done a lot by DD mechanics. I wish you the very best turn out.
Tim is on the money. Since the boat is out of the water now? Take your best educated guess on propping pitching etc. Roll the dice on whether you believe the engines are attaining high idle. With all the records I'd gamble on them being able to hit max high idle. And proceed accordingly. Just another day working on the boat. Please let us know the outcome..
When we surveyed my 43' DCFB with 671- N's, I had Tom Hugg (a great DD guy) doing the engine survey. He had us run both engines up to no load WOT for a few seconds. Made a really cool sound!
They sounded like jet engines winding up!! Well at least to me they did.
Really glad I got the engine survey which included compression checks of each cylinder. There were no maintenance logs and very little documentation for work done on the boat.
Jon
Doing any prop work before doing a complete engine tune up is most likely a waste of time and money. Adjust the valves and injectors, set the racks, and verify low and high idle to your engine specs. Few things are more fun ( or noisier) than standing next to a Detroit when it is run up to high idle speed at the dock.
Have the spares checked out. You definitely have a prop issue with mismatched props but I doubt you'll get it right without some engine work or adjustments. Even if you take a guess at prop pitch you'll be better off with a matched set. But you need to start from the top with the engines. Start with new fuel filters, both primary and secondary. Most likely dirty given the lack of use. Make sure you don't have any air restriction. Absolutely do a no load test. If your not hitting 2450-2500 no load find out why. Make sure you're getting full travel on the throttles. I would have all the injectors tested and replace any that are bad. Then set the rack. All of this should be done as routine maintenance. Did your surveyor document any engine data while running? Any fluctuations in exhaust temps under higher loads say 1800rpms and up? How is the oil pressure and what coolant temps do you see at 1800-WOT?
I will definitely have the spare props checked. 12v71's max RPM is 2300. Entire fuel system was gone through just 20 hours ago, I replaced all the racor's and engine mounted filters, they still look surprisingly clean. I do need to clean the airsep's, will be done tomorrow with plan to reroute crank case hose to a puke can.
Hopefully will be splashed tomorrow afternoon where I intend to do the no load test (looking forward to that). I'm sure I will have results to report back with. Thanks to everyone for the feedback
I have confirmed the starboard temp gauge is incorrect--IR thermo reflects 182 degrees at WOT