Reply With QuoteI'll try again, 95 looks and no replies?
I'd love some input on whether my boat is running with numbers that make sense.
I'm running a 19 ft. Avenger with mild 455, logs, 12JC with A impeller. I just installed a hydraulic Place Diverter. Before diverter I had 4,400 rpm and 53 mph, after diverter 4,400 rpm and 56 mph on gps. I have a 9 quart pan but no oiling mods, so I limit the full throttle runs to 20 seconds or so then bring it down under 3,500 rpm, hopefully this will keep it alive.
My pump has problems I need to address, needs bowl bearing seal, thrust bearing grease seals. When I look in the hand-hole the impeller edges look very worn and jagged.
Do these numbers look normal for a boat like this with quite a bit of wear on the pump? I'm thinking of attempting a pump rebuild myself with the rebuild kit from CP. Anything that will trip me up badly if I try this myself?
I'm having a blast, the boat rides so much better with the diverter. Thanks in advance for any comments.
I'll try again, 95 looks and no replies?
Avenger,
I am also running a mild 455 with 12JC pump, 19' Hawaiian. Unlike you
I am running a fairly fresh American Turbine AA impeller with no diverter.
I am getting 57mph on the speedometer, haven't had access to the humiliator (GPS) yet.
IMHO you have room for some good gains.
My thoughts on your numbers in comparison to mine:
1) The design and condition (hook, etc.) of the hull is a big variable for speed that I can't really meaningfully compare.
2) I don't have a diverter, and you should be getting an extra 3 to 5 mph just from using the diverter right.
3) Generally speaking your smaller impeller should also be giving you a little more RPM and a little more top speed. (I chose a larger impeller for hole shot and engine life).
4) A worn out impeller with sloppy clearance can rob a lot more efficiency than you might expect. I have read numerous stories of guys who have rebuilt their pump with this or that hardware, but no matter what they used they are always enthusiastic about the increase gained from a tightened up pump. The only exception to this is when radically poor choices have been made in impeller sizing. An A impeller is a good "all around" choice for boats like ours. I think AA is even better for an Olds unless you have oil return modifications done.
5) If you take your time and follow the instructions you will have no problem rebuilding the pump yourself. Occasionally people need special tools to get stuck parts off, etc. but generally a basic rebuild is a pretty simple job.
There is an excellent and free illustrated guide to doing a rebuild on www.americanturbine.com that you can download in .pdf format. I also have the Seloc manual, but found the AT version to be more helpful and $30 cheaper. If you run in to any confusion during the rebuild just search the forum or post up your question. The HB crew usually responds pretty quickly to specific questions, and there is a wealth of material in the archived posts.
6) Whatever you do keep oil in the Olds and grease your thrust bearing!
Good luck with the project :boxed:
Thanks for the comments, El P. Comparing to another 19 ft. with Olds is perfect.
What RPM are you running with your AA? I'm tempted to go for the AA, will make for better cruising and safer with the Olds. But, I think I would miss the top end if it dropped more than a few mph, and a new A on rebuilt pump will probably lower the max rpm's a bit anyway.
I have the Seloc manual, will look at the AT site, thanks for the tip. I can't decide whether to do it now or wait until the end of the season, but either way I've got to fix the bowl bearing seal so I can keep oil in it. Is the CP kit the way to go on the rebuild?
I do grease the thrust bearing often, but the seals must be gone as grease runs out the back pretty quickly. Shouldn't do any harm, I'm more worryed about the non-lubricated bowl bearing right now.
Avenger,
Check and see if you carb is opening all the way at full throttle and check fuel flow. Quick, cheap and easy check.
I would think you should be able to see at least 4500-4600 rpm's in mild form with your 455. I think you have more in there somewhere.
Speed vs rpm's seems fairly efficient with 4400r's to 56 mph. But I would expect more rpm's.
I checked today and the throttle seems to be opening fully. Problem might be total timing, It's 28-29 degrees total and most of what I read here suggests 30-34 total, I'll adjust timing to 32 degrees and see if any difference in WOT rpm and general performance.
I checked today and the throttle seems to be opening fully. Problem might be total timing, It's 28-29 degrees total and most of what I read here suggests 30-34 total, I'll adjust timing to 32 degrees and see if any difference in WOT rpm and general performance.
not possitive,but my avenger with a stock 460 has about the same numbers.maybe it is the hull bottom of this kind of boat.
not possitive,but my avenger with a stock 460 has about the same numbers.maybe it is the hull bottom of this kind of boat.when ya get the flywheel fixed, gps that dude steve!i wanna know the numbers myself on yours.that way we'll have some base numbers to compare and see what this winter's mods do for ya!
The other interesting number for me is rpms at planing speed. It takes about 3000 rpms to get on plane even with the diverter almost all the way down. Once on plane I can hold it with about 2600-2700 rpms, no less. I'm wondering if this will stay the same with a new A impeller or what a AA impeller would do.
finish the season and rebuild the pump this winter, I'ts not that hard, and you wont be rushed to git it done. you can get rebuild kits from a number of places. shop around, there's plenty of free advise out there,the hardest part is gitting it apart. I did mine and am vary happy with the results,good luck steve.
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