Well Jim...finished my homework and am ready to focus on my prop first and give my 68 a needed holeshot boost. I'll post pics of my carb later. Here are my outdrive/prop findings: Full Throttle RPM: 4000 (which gets me about 45-47mph) Prop Pitch: Not yet measured, but a "23" is stamped right on the face of it as expected. I'm taking it into a prop shop this week to verify the pitch for you. The shop cautioned me about redlining if I go to far in the other direction. Can't find anything in the manual on that. I have all original manuals -- the one for the Aquamatic 200 states a reduction ratio of 1.59:1 and a 15-in max. prop diameter if that helps. Pictures of prop and shaft below:
Thinking about Jim's loss a lot this week offering my sincere condolences to him and his family and others who knew Jim Jr. Thoughts and prayers also with those here in Mpls that are waiting to hear about lost loved ones that were simply at the wrong place at the wrong time on a bridge I cross at least twice each week with my family. Sure puts into perspective the insignificance of prop sizing but we shall proceed. Local prop shop measured up my 15 x23 and recommended a left-turn 15 x 19 long shaft aluminium for my Volvo for a dramatic improvement. Ordered one that I should get next week. Wish me luck but wish others more that really need some right now. On a lighter note...learned an expensive lesson this week about my Dyne. Apparently accidently leaving the boat key in the on position without the engine running for over 2 hours is hazardous to the supercoil. Wondered why it wouldn't start and clear fluid was all over the floor of my engine compartment. Took it in to find a completely melted coil. Hopefully that's it for a while.
Thanks for the kind words, I will be back on here on a limited basis and I will attempt to answer some questions. It is a good distraction for me. You should replace the points and condenser also and have the engine re-timed. That is a good choice for a prop as a starting point. I think the max rpm for the volvo is 4400 rpm and you would probably exceed that if you hold it open for a while. If it were mine I wold not exceed 4500 for long runs, I don't think 5000 would hurt it for short bursts, but that is the hot rodder in me. If it still does not pull hard enough then you could have the cup removed from the prop. This is easy with an aluminum prop and the Hydrodyne hull like a prop with no cup. It could also be repitched to a lower number for more thrust. Those two steps will increase the max rpm even more. I think we need to understand that in some cases the best ski prop will let the motor over rev on the top end and the only way to limit it in that case is your right hand. jim
It's hesitation is puzzing in that I don't have any points to replace after upgrading to electronic ignition this last Spring and the timing was set according to the manual spec unless you think we ought to deviate. It revs quick and smooth in neutral -- only under power does it not respond quickly. Here are some pics of the carb as requested should you see or think of anything that should be addressed. Also here's a shot of the new/old prop. New aluminum 15 x 19 has much longer blades that don't allow any open space when looking straight through the prop. Didn't get a chance to test the holeshot as a skier last week due to a temporaty shoulder sprain, but it's quicker out of my lift in reverse and the RPM have increased to about 4400 at about 45 mph. Great classic boat -- again, just trying to maximize it's potential. Thanks for the input. Dave
Is it possibly the jetting or mixture? My initial guess would be it's just a touch rich. Have you looked at the plugs for color and any signs of liquid after warming up fully and hauling @$$ across the lake?
Your problem could be in the accelerator pump or the idle transfer circuit. The three links below have fairly good descriptions of these circuits. The third link has a good description of the idle transfer circuit, but the accompanying description of the accelerator pump circuit is not accurate for Holley. The first two links describe the Holley accelerator pump circuit pretty well. Assuming that the carb ran good at some point, I would not modify any thing yet. I would clean out the two mentioned circuits with an automotive carb cleaner in a pressure can with the thin plastic tube attached. First identify the circuit and blow it out with the cleaner and compressed air. The idle adjustment screws should be screwed all the way in and the number of turns recorded. Then remove the idle adjustment screws to help with the cleaning process. If the float bowls are removed in this process, there are special marine gaskets between the bowl and the body that need to be replaced. If the metering plates are removed there is another special marine gasket. The metering plate is between the float bowl and the main body. If you are in the right store, there should be no need to buy a whole gasket kit. The gaskets should be available separately. There are several different metering plate gaskets. Take the old one with you and make sure all the holes are the same. There are some detailed books available at most hotrod shops dealing with Holley carbs. If you are not familiar with them the books are a very good idea. http://www.stockcarracing.com/techartic ... djustment/ http://www.automedia.com/Holley_Tuning/pht20000718hm/1 http://www.chevyhiperformance.com/techa ... or_basics/ jim
