Top speed run with B1 26 pitch
#21
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Your logic makes sense to me. Why don’t you wait to order props? See where you are with all cylinders.
#23
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#24
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#25
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Right. Forgot that you borrowed props.
#26
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I don't believe the plunger on 1 lifter will solve the 200RPM difference. But your logic does make sense. I'm dealing with a 400RPM difference currently. I have another set of new 26's, a set of Mercury Racing labbed 28's, a set of B Blades labbed 28's and a stock set of 30's. And of course the 26's you have.
#27
Found out that one engine is not operating at 100%. I'm in the process of fixing that and it brought up a question in my mind. The starboard engine runs about 5300 rpm and the port was about 5100 rpm. If I get the port to run equally with the other that maybe the overall rpm of both would go up? Does that make sense? I am thinking that the starboard engine could only reach 5300 because it's being held back by the other? If they both are running the same could I expect that both of them may turn 54-5500 rpm? I ask mainly because over the winter I will be ordering my props. I also really want to run 80 mph. I could do with the 26's if the rpm would come up. The info above is using 26's. Thanks for your help and comments.
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#28
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Is the rule of thumb about adding or subtracting 2" of pitch equaling approx 400 rpm linear?? From my almost "$2,000.00 now experience" it's not. I am wondering if the jump to 28" pitch props is an exponential jump in the boating world.
Last year I borrowed a set of 28's and a set of 26's both B-1's and both sets of props didn't really match each other as a set whether different years and Mercury changed the style of the blades or maybe some repairs were made to one and not the other. The point is both sets were used, visibly different from each other and unknown history. Both sets ran fine in fact, both of these sets rendered better top speeds than these new ones.
Based on last years performance and my goal of running a WOT of 5k rpm I bought 28" B-1's. Seemed like a logical move because I was running around 53-5400 rpm with the 26" and the speed was 78mph. I was really hoping to bury my speedo at 80 with the new setup. I finally get out on the water with the new props and my speed is down to about 73 and the rpm is 44-4500. My disappointment at that moment couldn't be measured....
The first question is always about trim and I know there are variables so this is just FYI. I have the mechanical indicators for drives and I am just above 7 out of 8 so it's trimmed out pretty far and feels like it too. I don't have any problems getting on plane with the 28's and the mid range cruise is fantastic! At 3600 rpm I'm running 60 mph. That used to be my wot speed! Carbs are mechanical secondary's and are opening fully. I did bump the timing from 33 last year to 35 degrees all in this year. Normally that makes the engines run stronger right? AFR's are in the mid 11's. Last year with the carb issues I think the AFR's were in the 10's. It was pig rich everywhere.
So my question is whether its better (good idea) to have these 28's changed to 27's or just buy the 26's? Maybe a new set of 26's would run at the 5k rpm I'm looking for?
Neither will happen this season because the 26's were out of stock till the fall and I'm hoping to get some actual boating in this season and don't want to wait for these 28's to get altered.
As always, I appreciate your help and input.
Last year I borrowed a set of 28's and a set of 26's both B-1's and both sets of props didn't really match each other as a set whether different years and Mercury changed the style of the blades or maybe some repairs were made to one and not the other. The point is both sets were used, visibly different from each other and unknown history. Both sets ran fine in fact, both of these sets rendered better top speeds than these new ones.
Based on last years performance and my goal of running a WOT of 5k rpm I bought 28" B-1's. Seemed like a logical move because I was running around 53-5400 rpm with the 26" and the speed was 78mph. I was really hoping to bury my speedo at 80 with the new setup. I finally get out on the water with the new props and my speed is down to about 73 and the rpm is 44-4500. My disappointment at that moment couldn't be measured....
The first question is always about trim and I know there are variables so this is just FYI. I have the mechanical indicators for drives and I am just above 7 out of 8 so it's trimmed out pretty far and feels like it too. I don't have any problems getting on plane with the 28's and the mid range cruise is fantastic! At 3600 rpm I'm running 60 mph. That used to be my wot speed! Carbs are mechanical secondary's and are opening fully. I did bump the timing from 33 last year to 35 degrees all in this year. Normally that makes the engines run stronger right? AFR's are in the mid 11's. Last year with the carb issues I think the AFR's were in the 10's. It was pig rich everywhere.
So my question is whether its better (good idea) to have these 28's changed to 27's or just buy the 26's? Maybe a new set of 26's would run at the 5k rpm I'm looking for?
Neither will happen this season because the 26's were out of stock till the fall and I'm hoping to get some actual boating in this season and don't want to wait for these 28's to get altered.
As always, I appreciate your help and input.