Props and rpm
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- Aluminum Star
- Posts: 163
- Joined: Thu Sep 11, 2014 7:27 pm
- Location: Southern Indiana / Louisville
Props and rpm
As mentioned in a prior post...
Post ignition tune up engines no longer stalled once trannies are engaged.
Had a great afternoon on the river!!!
Once I knew the trannies / ignition were functioning I started to increase RPMs.
All good until 2900 rpm. After approx 2800 ( 20 mph according to iPhone gps speed app) engines would bog and not produce more forward thrust/power.
I think the spare props are 17 x 19 .... But I will have to verify.
Like a dummy I did not check the current props before splashing.
Our seems to be a little odd in the cid / trans ratio dept. and I am not sure what prop would have been stock.
I would prefer fuel efficiency over power / speed.
Any thoughts?
Post ignition tune up engines no longer stalled once trannies are engaged.
Had a great afternoon on the river!!!
Once I knew the trannies / ignition were functioning I started to increase RPMs.
All good until 2900 rpm. After approx 2800 ( 20 mph according to iPhone gps speed app) engines would bog and not produce more forward thrust/power.
I think the spare props are 17 x 19 .... But I will have to verify.
Like a dummy I did not check the current props before splashing.
Our seems to be a little odd in the cid / trans ratio dept. and I am not sure what prop would have been stock.
I would prefer fuel efficiency over power / speed.
Any thoughts?
1984 32' Sedan FB
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
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- Aluminum Star
- Posts: 163
- Joined: Thu Sep 11, 2014 7:27 pm
- Location: Southern Indiana / Louisville
Re: Props and rpm
Or if anyone has any thoughts as to what this prop ratio will produce rpm / power / speed / efficiency wise.
I see that 16 x 16 should have been stock.
I see that 16 x 16 should have been stock.
1984 32' Sedan FB
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
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- Royal Aluminum Star
- Posts: 266
- Joined: Mon Jan 19, 2015 11:07 pm
- Location: Lake Superior-Michigan's U.P.
Re: Props and rpm
I don't know if you did this already, but I would check the timing on the motors and make sure the choke plate is fully open and the 4 barrels are opening up properly. On a different boat I have, mine would bog down when I reached the 4 barrels, they were actually opening up, but I wasn't getting any fuel out of the jets. I filled the carb vents with sea foam and let it sit for a few days and the problem was gone. I also dump sea foam in the vents during lay up to hopefully keep them from gunking up over winter.
Rodney
1975 28 Express-Twin 350 Chevy's, SOLD
1990 32 Express--Twin Mercruiser 454 with Bravo I outdrives
Portage Canal Waterway-Upper Peninsula,Lake Superior
1975 28 Express-Twin 350 Chevy's, SOLD
1990 32 Express--Twin Mercruiser 454 with Bravo I outdrives
Portage Canal Waterway-Upper Peninsula,Lake Superior
Re: Props and rpm
I hope those aren't 19 pitch props on there!
Jeff
Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
Re: Props and rpm
My 32 footer with the same motors has 17 x 15s and the motors only hit 3,900 rpms WOT (which is fine by me--the boat leaps out of the water).
Jeff
Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
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- Aluminum Star
- Posts: 163
- Joined: Thu Sep 11, 2014 7:27 pm
- Location: Southern Indiana / Louisville
Re: Props and rpm
So, given the specs on our , what would the consensus be for fuel economy but with enough to power to handle the Ohio River currents....if that ratio exists.
I still need to get to her and confirm spare prop size as well as check that all four barrels are putting fuel into the system.
I still need to get to her and confirm spare prop size as well as check that all four barrels are putting fuel into the system.
1984 32' Sedan FB
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
Twin Chrysler 360's
1.52:1 Velvet Drives
Raw water cooled
Ohio River
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- Site Admin
- Posts: 410
- Joined: Sat Jul 12, 2014 6:18 am
- Location: Kentucky
Re: Props and rpm
16x15 was stock per Marinette site.
17x19 is pretty steep. Too much bite lots of strain on engines.
Should be a nice grove having them
Pitched to 14 or 15 like Jeff s were.
Dave
17x19 is pretty steep. Too much bite lots of strain on engines.
Should be a nice grove having them
Pitched to 14 or 15 like Jeff s were.
Dave
1987 Marinette 29 FB Sedan
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain
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- Tin star
- Posts: 41
- Joined: Mon Jul 14, 2014 9:51 am
Re: Props and rpm
Ben, my 84 Model with 318hp was running best with 14x9 DynaQuad 3 blade cupped. I tried 14x10 also.
New Endeavor
1991 41ft Aft Cabin
Louisville,Ohio River
1991 41ft Aft Cabin
Louisville,Ohio River
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- Tin star
- Posts: 41
- Joined: Mon Jul 14, 2014 9:51 am
Re: Props and rpm
Correction, 318ci Twins and at WOT 4000 to 4200 RPM. Ran it hard for 10 years with no problems except moisture in Distributor caps and changing impellers every year.
New Endeavor
1991 41ft Aft Cabin
Louisville,Ohio River
1991 41ft Aft Cabin
Louisville,Ohio River
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- Site Admin
- Posts: 410
- Joined: Sat Jul 12, 2014 6:18 am
- Location: Kentucky
Re: Props and rpm
14 inch wheels are used on 1:1 transmissions
16 inch wheels are used on 1.5: 1 transmissions
I do not believe he mentioned which gear he had?
dave
16 inch wheels are used on 1.5: 1 transmissions
I do not believe he mentioned which gear he had?
dave
1987 Marinette 29 FB Sedan
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain