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| Starboard engine trailing off |
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Message |
    
Garrett Jones
New member
Username: grrttjn
Post Number: 3
Registered: 05-2009
| | Posted on Saturday, October 24, 2009 - 01:14 pm: | 
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Details:
1977 Silverton 28' Sedan w/ flybridge
Twin 220 Crusaders - original engines
Beginning of the 2009 boating season we just replaced the distributors and went to electronic ignition...GREAT results.
Here we are at the end of the season - - the temps on lake MI has been less that warm to say the least. The last two times we have been out (mid/upper 30's to low 40's) both engines have run great...I gave them a bit more time to warm up due to the outdoor temps...rather be safe than sorry. Everything goes great...can cruise at 2000 RPM's...no problems. When I push it a bit more...just over 2200 RPM's, my normal cruising speed, the starboard engine trails off...first you can hear it and then you start to see it on the tach. You can pull the throttle back and it will slowly recover but if you try and push the throttle forward to get through it, it is worse than pulling back on the throttle. In fact trying to push through it is a good way to nearly kill it completely. I have never actually lost the engine and with this being a new problem, I am not sure where to start.
Not knowing what to do, I did replace the fuel filters. That is about the extent at the moment. Would love to have things cleared up before putting it to bed on Monday. Let me know your thoughts and thanks in advance guys! |
makomark
Senior Member
Username: makomark
Post Number: 1756
Registered: 09-2008
| | Posted on Saturday, October 24, 2009 - 02:31 pm: |
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try these:
Fuel pump worn out - how old?
fuel pickup anti-syphon valve causing fuel flow issue.
Fuel pickup tube's strainer block with crude from tank.
Fuel line collapsing internally restricting flow.
If separate tanks, vent tube full of fluid or fitting restricted.
Could also be a bad joint/connection in the fuel line leaking air in as the pump tries to pull the fuel to it.
You could always use an outboard tank to temporarily supply the pump. If that causes the problem to go away, you know which area to check. A Fuel pressure gauge is also beneficial in diagnosing these types of issues. Make sure you check it at rpmm, under load, and not just at idle. |
Chuck Hanson
Advanced Member
Username: chuckhanson
Post Number: 139
Registered: 10-2007
| | Posted on Saturday, October 24, 2009 - 05:39 pm: |
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Someone reported that their pickup tube dropped off and although they had fuel in the tank, they had no way to get it to the engine. Since that time I have carried a length of 3/8 inch copper tubing and some rubber hose that I can insert through the gas cap and set up a temporary fuel line to get me back home. Although I have never used it, I feel more comfortable having it.
You could rig up something like this to eliminate the question of plugged fuel lines, filters etc. After use you would have it in cases of emergency.
I did have a kink develop in the fuel supply line while on a 700 mile trip on the Mississippi River and Tom Bigbee waterway. I could only get about 1400 RPM. I finally pulled over to the bank, tied off to a tree and started looking for the problem. When I found and eliminated the kink, everything went back to normal. I eliminated all but a very short length of hose in my fuel supply line. Interestingly when everything was cool it ran almost perfect. As the engine compartment warmed up the hose became more flexible and the kink shut the flow down.
Suggestion: Make sure you don't have any kinks in the supply line.
Good hunting,
Chuck |
Bondo
Senior Member
Username: bondo
Post Number: 2079
Registered: 12-2006
| | Posted on Sunday, October 25, 2009 - 08:52 am: |
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" I did replace the fuel filters. "
Ayuh,... Did you Inspect the contents,..??
Whatever was in them may have already migrated to the Carb, causing the problem... |
Al
Advanced Member
Username: knuckle47
Post Number: 752
Registered: 09-2007
| | Posted on Sunday, October 25, 2009 - 06:09 pm: |
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Bondo, Nice to see you again, Al |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 6992
Registered: 09-2003
| | Posted on Monday, October 26, 2009 - 06:33 am: |
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Bondo: Where you been, man? Take up sailing or something?
Garret: Your problem sounds like classic fuel starvation. If the ice holds off a day longer up there in the frozen North, you could try this: When the motor starts to sag like that, have someone manually close the choke a bit--not all the way, but just a bit--to see if the motor picks up. If it does, start looking for why it's not getting enough gas.
Jeff |
makomark
Senior Member
Username: makomark
Post Number: 1758
Registered: 09-2008
| | Posted on Monday, October 26, 2009 - 09:01 am: |
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That's a great test to see if the carb is not behaving well.
If it makes no difference, the issue is upstream in the fuel system. |
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