| Author |
Message |
    
Tom Feil
New member
Username: vamerc14
Post Number: 1
Registered: 07-2009
| | Posted on Sunday, July 19, 2009 - 03:48 pm: | 
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This is the second time out for the boat this year. First time it started fine and ran well at all speeds. A month later it started fine and when I started up the lake it suddenly bogged down. I restarted it easily but when I put in gear it bogs down just barely above idle speed. When it is not in gear it will go above 1200 rpms but once you put it in gear and try to go forward it bogs down. I rode around the lake at low speed thinking it might clear but it never went much faster that idle speed. Repumping the bulb from the tank had no effect as did pushing in the choke. Will a fuel problem occur suddenly like this or could I have some sort of electrical problem that wont allow the engine to run at higher speeds? I rebuilt the carbs and fuel pump 3 years ago and it has been running fine. |
Martin Van Meenen
New member
Username: martin_vm
Post Number: 1
Registered: 08-2009
| | Posted on Thursday, August 13, 2009 - 02:06 am: |
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Tom, did you find the problem? I am having the same problem on the same engine. Works and runs great in neutral, as soon as I put it in gear it bogs down after 1200 rpm. We replaced plugs, reset and cleaned carbs, checked fuel system - still the same. |
Noel McBride
Advanced Member
Username: haventaclue
Post Number: 252
Registered: 05-2007
| | Posted on Thursday, August 13, 2009 - 04:36 pm: |
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Sounds like a clog in the high speed jet,I know you said you cleaned the carbs but it's unknown for a clog to happen after a cleaning. |
Tom Feil
New member
Username: vamerc14
Post Number: 2
Registered: 07-2009
| | Posted on Sunday, August 16, 2009 - 09:49 pm: |
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No, I have not had a chance to work on it. Until you posted your note I had not received any hints on where to start. It seems unusual that all three carbs would have clogged high speed jets at once in my case especially after it ran fine the first time out this season. I had intended to order the parts to rebuild the fuel pump since it may not be getting enough pressure at higher speeds unless someone thinks this is wasted effort. |
Noel McBride
Advanced Member
Username: haventaclue
Post Number: 255
Registered: 05-2007
| | Posted on Monday, August 17, 2009 - 01:12 pm: |
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I'm not sure if your stator has high speed windings,but maybe check stator. |
Noel McBride
Advanced Member
Username: haventaclue
Post Number: 256
Registered: 05-2007
| | Posted on Monday, August 17, 2009 - 01:29 pm: |
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" I rebuilt the carbs and fuel pump 3 years ago and it has been running fine." I just reread you post.
I think another rebuild of the pump and carbs,maybe a diaphram on the way out. Also might be a good time to do the impeller as well if you haven't done that in three years.But still check the stator. |
John Thalheimer
New member
Username: jt_hammer
Post Number: 1
Registered: 08-2009
| | Posted on Thursday, August 27, 2009 - 03:08 am: |
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Tom, check the fuel line going to the filter.
I have a similar problem, bogs down at WOT and then I ease back for 10 or twenty seconds and it clears up. I go back to WOT and it runs good for a little bit and same thing happens. I replace fuel line and primer bulb from tank to engine, had the carbs cleaned and it still bogs down. I finally located the fuel filter and notice the line going to the filter should have been a 90 degree, but looks like it was straight and had a kink in the line. When I pulled the line and looked through it all I saw was black junk. So hopefully when I get a new line and filter it will run better.
My engine is a 60 hp 1997 Mercury Bigfoot OB |
Tom Feil
New member
Username: vamerc14
Post Number: 3
Registered: 07-2009
| | Posted on Monday, September 07, 2009 - 08:44 am: |
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So I cleaned the carbs, rebuilt the fuel pump and put some "sea foam"in the gas to take care of any water in the tank. It starts fine and idles fine but when you put it in gear and try to go above no wake speed it bogs down and kind of misses. I ran it for 20 or 30 minutes and it did not clear itself. Since it originally stalled out at high speed after running fine the first trip out this year I am wondered if it is some sort of electrical issue that may control timing advance or something. This may be beyond my ability to troubleshoot. Any suggestions? |
Noel McBride
Advanced Member
Username: haventaclue
Post Number: 282
Registered: 05-2007
| | Posted on Monday, September 07, 2009 - 06:38 pm: |
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Tom if you haven't touched the timing it is unlikely to be that.Test the stator with an ohm meter,when the stator is cold it works ok but as it heats up the windings expand and if there is a break in the windings it opens,should have continuity, then heat the stator with hair dryer,hi Graham,if you lose continuity,you have a problem with the stator. |
JB
Senior Member
Username: beckerjs
Post Number: 1892
Registered: 11-2005
| | Posted on Monday, September 07, 2009 - 08:31 pm: |
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did you check for spark on all, and compression? |
Martin Van Meenen
New member
Username: martin_vm
Post Number: 2
Registered: 08-2009
| | Posted on Tuesday, September 08, 2009 - 12:13 am: |
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I think we were able to resolve the issue on my boat - same challenge - bogs down after 1200 rpm. It turns out we had one low speed jet clogged, but most importantly the high speed jets were out of synch with the low speed jets. When the boat is idling or in neutral it uses its low speed jets, when in gear and reving up beyond neutral range - the high speed jets kick in. If these are not syched they fire out of sequence and cause what we have seen. Yes it took a mechanic to do the work. |
Tony Delio
Senior Member
Username: tonyob
Post Number: 1516
Registered: 05-2001
| | Posted on Tuesday, September 08, 2009 - 02:17 pm: |
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I think Noel is on to something when he mentions that the stator may have high and low speed windings; it does. Check the output at the blue and red wires at the switchbox. The blue wire is the low speed and the red is high speed. At cranking speed should read 20V at red wire, 180Vat blue. |
