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Nichevintage
Joined: 24 Jul 2017 Posts: 9 City/Region: Bellingham
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
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Posted: Mon Jul 24, 2017 3:25 pm Post subject: New 22' Cruiser Owner Here - Question on the RPMs of Johnson |
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Took the boat out in puget sound first time this weekend. Wind 5-10knots, wind waves 1'-0" and couldn't get the Rpm's over 4200 at WOT. This is a 1991 with original Johnson 70. Top speed was about 14-15 MPH. Just felt like a dog... We did have 5 adults and full tanks of fuel. I also noticed the kicker wasn't fully retracted when we pulled out. Were we overloaded or is there some sort of rev-limiter on the old Johnson, or just a combo of the kicker, weight, and old motor?
Plans to re-fresh with a 4-stroke Honda next year but sure would like to get some life out of the Johnson for another year. |
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nordicstallion
Joined: 16 Dec 2007 Posts: 380 City/Region: Crescent City
State or Province: CA
C-Dory Year: 2004
C-Dory Model: 19 Angler
Vessel Name: Rylee Rose
Photos: Rylee Rose
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Posted: Mon Jul 24, 2017 5:07 pm Post subject: |
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I have a 70 hp on my 19 & am sometimes dissapointed in performance, but only in a following sea, tanks always full. We have a big reef with lumpy water here so wot speed generally not possible. Sounds like you have quite a boatload & with a 70 on a 22 I wouldn't expect much more. If I were to repower I'd go with something larger. Etec 90 maybe. Does your kicker drag in the water? Could matter but I think underpowered & overloaded is your problem! |
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Nichevintage
Joined: 24 Jul 2017 Posts: 9 City/Region: Bellingham
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
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Posted: Mon Jul 24, 2017 5:38 pm Post subject: |
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Thanks for reply. I'm going to try the lake with my wife & I and see the comparison. Plus got the kicker up in its top position now. Newbie jitters I guess! |
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thataway
Joined: 02 Nov 2003 Posts: 20810 City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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Posted: Mon Jul 24, 2017 6:02 pm Post subject: |
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Agree, take the boat out light and see what the speed is--you should get in the low 20's at WOT. Should be cruising at least in the high teens at 4200.
Is the fuel fresh? How about plugs? --probably need change if not new. The kicker can make a difference. What shape is the prop in? Are there trim tabs? How was the motor trimmed--down for first getting on a plane, as RPM pick up--trim up for max speed. Eventually you will want trim tabs. When you get the new 90 HP you will probably want to get a Permatrim foil to get the most out of the boat.
I suspect with a lighter load, and some fiddling around with the trim, you will do much better.
The WOT on that 70 should be in the 5500 range. _________________ Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
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homerjack
Joined: 12 Mar 2011 Posts: 186 City/Region: Homer
State or Province: AK
C-Dory Year: 1988
C-Dory Model: 22 Cruiser
Vessel Name: 49er
Photos: 49er
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Posted: Mon Jul 24, 2017 9:39 pm Post subject: |
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Only time that happened with my old 70 was when I had a dirty bottom...er that is boat bottom. Have you checkwd lately. Lots of algae this time of year if kept in water. And yes that's a lot of avoir du pois to haul. |
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Ordutch1975
Joined: 06 Jun 2017 Posts: 255 City/Region: Portland
State or Province: OR
Vessel Name: Boatless :-(
Photos: PennyBridge
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Posted: Mon Jul 24, 2017 10:27 pm Post subject: |
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What size and pitch prop? If the prop is the wrong size you can have these kinds of symptoms. Though I would agree a 70 with that many people might be a bit of a stretch. _________________ "And it is an interesting biological fact that all of us have, in our veins the exact same percentage of salt in our blood that exists in the ocean, and, therefore, we have salt in our blood, in our sweat, in our tears. We are tied to the ocean. And when we go back to the sea, whether it is to sail or to watch it, we are going back from whence we came. " -JFK |
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Nichevintage
Joined: 24 Jul 2017 Posts: 9 City/Region: Bellingham
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
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Posted: Tue Jul 25, 2017 2:24 am Post subject: |
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So took it to the lake this evening, and indeed got to a max speed 26.2 MPH with just my wife & I and still 3/4 full tanks. WOT was around 5200 RPM. Indeed we had it overloaded. So thinking 2-3 adults is probably going to be the max with full tanks of fuel. Agree to continue to do a little fiddling around and probably change the plugs as well which can't hurt. I can tell it feels under -powered which is tough coming from a V-6 ski boat that will hit 45-50 MPH like nothing but understand that this is a cruiser not a fast-boat. |
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Nichevintage
Joined: 24 Jul 2017 Posts: 9 City/Region: Bellingham
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
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Posted: Tue Jul 25, 2017 2:31 am Post subject: |
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Ordutch1975 wrote: | What size and pitch prop? If the prop is the wrong size you can have these kinds of symptoms. Though I would agree a 70 with that many people might be a bit of a stretch. |
It's a 13-3/4 x 15 Thoughts? I don't know if that is appropriate for the ol' Johnson or not. There is another prop in the boat I could check out tomorrow... |
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Nichevintage
Joined: 24 Jul 2017 Posts: 9 City/Region: Bellingham
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
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Posted: Tue Jul 25, 2017 2:33 am Post subject: |
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homerjack wrote: | Only time that happened with my old 70 was when I had a dirty bottom...er that is boat bottom. Have you checkwd lately. Lots of algae this time of year if kept in water. And yes that's a lot of avoir du pois to haul. |
Bottom is squeaky clean. Kept on the hard. |
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Ordutch1975
Joined: 06 Jun 2017 Posts: 255 City/Region: Portland
State or Province: OR
Vessel Name: Boatless :-(
Photos: PennyBridge
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Posted: Tue Jul 25, 2017 11:15 am Post subject: |
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Your WOT at 5200 and 26 sounds pretty good with the two of you. I would agree overloaded with that many people and a 70. Your prop is likely just right.
If you want to carry that type of load you'll want to re-power. |
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hardee
Joined: 30 Oct 2006 Posts: 12632 City/Region: Sequim
State or Province: WA
C-Dory Year: 2005
C-Dory Model: 22 Cruiser
Vessel Name: Sleepy-C
Photos: SleepyC
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Posted: Tue Jul 25, 2017 2:06 pm Post subject: |
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I have twin 40's, (so 80 total) and I would say that is the minimum you would want for power. 70 might work for a very light load but with 5 adults you are way overworking that little Johnny.
Harvey
SleepyC
_________________ Though in our sleep we are not conscious of our activity or surroundings, we should not, in our wakefulness, be unconscious of our sleep. |
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thataway
Joined: 02 Nov 2003 Posts: 20810 City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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Posted: Tue Jul 25, 2017 4:24 pm Post subject: |
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To carry more load--re prop--drop by 2" will probably bring the RPM up close to 5000 RPM. There are boats which are running 50 hp, and are able to plane, but at low speeds. |
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