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ssobol
Joined: 27 Oct 2012 Posts: 3375 City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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Posted: Tue Oct 06, 2015 1:56 pm Post subject: Honda BF90D won't run above 3400 rpm |
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Normally I operate my 22 cruiser at sea level (Chesapeake Bay). It has an 08 BF90D engine with about 200 hours on it. Last time I used the boat (about two weeks ago) everything worked fine. With the prop that is on it the normal WOT rpm is 5600.
This week I took the boat to a lake that has an elevation of about 1000' MSL. I found that the engine would not run above ~3400 rpm (about 12 mph). Below that speed it works fine. I cruised for a number of hours at 2000 rpm (~7 mph).
If I try to go faster the boat accelerates normally until about 12 mph, and then won't go any faster. The engine rpm peaks at ~3400 and then will fall off a bit if I keep advancing the throttle. When the engine is in neutral it will go above 3400 rpm with out any problem.
My question is am I experiencing difficulty because of the altitude or do I have an engine problem? I have not tried running the engine at the normal altitude yet.
If this is an altitude issue I would not have expected 1000 ft. to make such a big difference in the engine performance. I know that people who go to Lake Powell have to adjust their prop pitch to compensate for the altitude, but that is 4000' plus higher temps.
If this is an elevation issue, is there a way to predict/calculate the proper prop pitch in advance (i.e. pitch change/1000 ft)? |
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Spike
Joined: 21 Oct 2006 Posts: 572 City/Region: Kent
State or Province: WA
C-Dory Year: 2007
C-Dory Model: 22 Cruiser
Vessel Name: Bootleg Hooch
Photos: Bootleg Hooch
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Posted: Tue Oct 06, 2015 2:38 pm Post subject: |
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Sounds exactly like the problem I had 2 years ago with my 115 Yamaha, mine was ethonal related and the problems it caused in the VST. As I am not familiar with Hondas fuel systems I cannot say with any type of certainty, but the symptoms are identical _________________ Chuck
Bootleg Hooch |
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rogerbum
Joined: 21 Nov 2004 Posts: 5922 City/Region: Kenmore
State or Province: WA
C-Dory Year: 2008
C-Dory Model: 255 Tomcat
Vessel Name: Meant to be
Photos: SeaDNA
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Posted: Tue Oct 06, 2015 2:56 pm Post subject: |
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That doesn't sound like an altitude problem but rather something else. I'd suspected fuel starvation - maybe a clogged filter etc. _________________ Roger on Meant to be |
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BrentB
Joined: 15 Jul 2006 Posts: 4419 City/Region: Greenwood
State or Province: IN
Photos: BrentB
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Posted: Tue Oct 06, 2015 3:25 pm Post subject: |
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New gas or old? Ehtanol or E0? _________________ Brent Barrett |
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thataway
Joined: 02 Nov 2003 Posts: 20815 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 Oct 06, 2015 3:51 pm Post subject: |
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Not an altitude problem. I agree that it is a fuel problem. Start with filters, both in the line, and if there is any in the Honda 90, under the cowl. (This should be an injected engine. There may be a filter or water separator under the cowl). Next, you look at the fuel hoses, the selection valve (could be that it is a little off, Port or Stb..and restricting. How does the fuel primer bulb look, if fuel starvation before the valve, it will be flatter, or soft.
Other areas, include anti siphon valve, fuel hoses them selves, the pickup and the tank vents. It could also be a problem with the injectors or injector pump--but less likely. _________________ 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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colbysmith
Joined: 02 Oct 2011 Posts: 4557 City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
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Posted: Tue Oct 06, 2015 10:36 pm Post subject: |
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When I had that kind of problem with my Mercury 115 Efi 4-stroke it ended up being a bad pencil coil. Colby |
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Bill K
Joined: 28 Sep 2012 Posts: 314 City/Region: Toledo
State or Province: OH
C-Dory Year: 1989
C-Dory Model: 22 Cruiser
Vessel Name: NIC'L PIC'L
Photos: NIC'L PIC'L
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Posted: Wed Oct 07, 2015 8:43 am Post subject: |
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There is a fuel filter and a fuel water separator under the cowl on my 2013 BF90D.
Bill Kelleher _________________ KA8BFT |
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ssobol
Joined: 27 Oct 2012 Posts: 3375 City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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Posted: Wed Oct 07, 2015 2:00 pm Post subject: |
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Not long after I made my initial post, I went out again and the engine ran fine. The WOT rpm was about 5K. It seems that the BF90D switches modes or something about 3300 rpm, you can sort of feel it take off after that rpm.
It has run fine for about 7 hours so far. |
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