1997 sundancer 270da 7.4 mpi w/bravo iii

I understand the SR site has the correct prop specs for your boat. I cant imagine haveing trouble getting on plane with the BIII with proper props. Were they changed sometime? I'm stern heavy with full water and the 5k gennie and I still get on plane easily. MM
 
MonacoMike said:
I understand the SR site has the correct prop specs for your boat. I cant imagine haveing trouble getting on plane with the BIII with proper props. Were they changed sometime? I'm stern heavy with full water and the 5k gennie and I still get on plane easily. MM
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I purchased the boat in March, when I did my sea trial there were three aboard and very little fluids and only about 30 gallons of fuel. The boat seemed to get up on plane okay. Since then I added a custom swim platform designed for this model and year that extends 26 inches. A normal load with a full fresh water tank and at least 60+ gals of fuel with 4-6 people aboard there is definitely a problem getting up. The engine was recently tuned and trim tabs are working fine. When up on plane WOT is barely 4200 with the 24p props. Based on specs for this engine it should be approx 4600. After talking to several shops concerning this issue, all pointed to a 22p prop set which should help with the hole shot and also with the top end by increasing the rpm at WOT to hopefully about 4600.
 
I bought my Sea Ray 270 Sundancer brand new in 2001 with 7.4 MPI and Bravo III. It came with the 22 pitch SS props. I have no problem getting on plane with 100 gallons fuel, 28 gallons of water, 6 people, and full of provisions. I do not even have to touch the trim tabs. If just comes up on plane. If everything is OK on your boat, the 22 props should solve your problems.
 
Dick Whetstone said:
I bought my Sea Ray 270 Sundancer brand new in 2001 with 7.4 MPI and Bravo III. It came with the 22 pitch SS props. I have no problem getting on plane with 100 gallons fuel, 28 gallons of water, 6 people, and full of provisions. I do not even have to touch the trim tabs. If just comes up on plane. If everything is OK on your boat, the 22 props should solve your problems.
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Thanks for the reply
I have been told that the 1997 270 is a much heavier boat than those starting in 1998 and newer. Not sure how that affects my issue. Hopefully the 22p props will solve the issue, and that I can find a used set, since new are around $1000.
Nick Liberatore
 
The 97 dry weight is higher because dry weight is based on base options and the 7.4 was standard in 97, 5.7 in 98 and 99. Read the first post in the mid 90s 270 thread for a more detailed description of weight. MM

nlib49 said:
Thanks for the reply
I have been told that the 1997 270 is a much heavier boat than those starting in 1998 and newer. Not sure how that affects my issue. Hopefully the 22p props will solve the issue, and that I can find a used set, since new are around $1000.
Nick Liberatore
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I have been experimenting with props on my 270 which is the newer model. Some of the numbers I have so far are below:

with 24p ON BOARD: full water 40 gal, full fuel 100gal, 1 adult
TIME TO PLANE: 31-37 sec
RPM at WOT: 4800
LOWEST RPM TO REMAIN ON PLANE: 3400

with 22p ON BOARD: full water 40gal, 1/3 fuel, 2 adults
TIME TO PLANE: 22-32 sec
RPM AT WOT: 5200
LOWEST RPM TO REMAIN ON PLANE: 3200

I have the 22 p on right now and next time I fill up with fuel I plan on obtaining numbers again to equal the weight of the 24 p test run. The RPM are obtained from my dash gauge which I realize it not the most accurate. I kept the trim tabs up on both attempts. I made multiple runs up to plane with each prop - thus the range of times. Most of the 24 p trials were closer to the 37 sec mark and most of the 22 p trials are closer to the 22 sec mark. I suppose I could average the times out sometime. I still think it takes to long to plane but then again I compare it to my 20 foot cobalt that seems to be on plane instantaneously.

I too had problems with difficulty planing when more than 4 adults are on board. My priority is getting up to plane not top end speed, thus I prefer the 22p. My only concern is they allow the engine to get to a pretty high WOT. I cannot remember the WOT specs right now.

I may end up putting my set of 24p up for trade for some 22p.
 
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Thanks for the info. I am presently running a 24p prop set and the rpm at WOT is approx 4200. I am hoping that a 22p prop set will allow the rpm to increase to the recommended 4600, which should also allow for a better hole shot and an increase in top end speed.
 
I had a similar experience on my 98 270 with the 24's. Put on a set of 22's and have noticed a definite improvement getting up on plane, WOT in proper range. I'm running at 3600 feet elevation. Easily get 30 to 31 mph with full load and a weeks worth of provisions and firewood. Also have observed that coming out of 8 months of winter storage it takes a few miles to burn out the bottom of the tank, perhaps an ethanol separation issue that there is no way around at Lake Powell's marina fuel docks.
 
I believe the WOT for a 7.4 is a range of 4200-4600 rpm so the op is in the rpm range. The range probably is affected by weight, but over-revving is a bigger risk in my estimation . MM
 
MonacoMike said:
I believe the WOT for a 7.4 is a range of 4200-4600 rpm so the op is in the rpm range. The range probably is affected by weight, but over-revving is a bigger risk in my estimation . MM
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After talking to the owner of Swim Platforms, Bennett Trim Tabs, several marine mechanics and other 270 owners, I came to the conclusion that the 22p prop set was the direction to go. True, 24p props were used on this model from the factory but since this boat was designed prior to ethanol fuels, part of the problem is that it no longer is putting out the 300hp as originally rated and therefore a drop in performance. I did install the 22p prop set and did get back up to 4600 rpm at WOT.Top end speed improved about 1-2 mph. Getting out of the hole improved slightly with 4-6 aboard, 100 gal of fuel and fully loaded.
 
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