[Rhodes22-list] Poor throttle response
R Orkin
roryorkin at verizon.net
Thu Sep 4 19:04:16 EDT 2008
I am not smelling anything that suggests rich on fuel..
The automatic choke is suspect for sure..
I do not know if there is a separate mixture adjustment for idle .
if at idle and you suddenly crank it then it stalls right away.. does sound
more like fuel starved than too rich. It is a yamaha 9.9 .. I am going to
look at a parts diagram to see if it does have an accelerator pump.
I want to work around to the carb itself as a last resort. I am not going to
tackle it and it is hard to get anyone around here to look at it in less
than 2 weeks.. I can run like this till the end of the season but would like
to try to fix it in place.
R22RumRunner wrote:
>
> Or, it could be starved for fuel. How does the exhaust smell? Rich or
> normal?
>
> Rummy
>
>
> In a message dated 9/4/2008 6:10:15 P.M. Eastern Daylight Time,
> mweisner at ebsmed.com writes:
>
> Rory,
>
> I do not recall what specific engine we are discussing so all comments
> are
> of a general nature (not all outboards have an accelerator pump.)
>
> It sure does sound like too rich a mixture. Look for the choke. Follow
> the
> actuator mechanism if you have to - the choke is somewhere at the air
> intake
> of the carb. It usually looks like a disc in a tube that rotates to
> close
> off the air intake during cold starting. When fully open you should be
> looking at the thin edge of the disc. When fully closed, you should be
> looking at the "top" (flat portion) of the disc, as it blocks most of the
> air passage. Partial choke setting opens the choke mechanism to some
> degree.
>
> Air filters in many outboards are actually in the housing. If your
> engine
> runs fine until you replace the housing, look for a very clogged air
> filter.
> If the air filter was the problem, the engine probably would not run at
> high
> speed at all.
>
> The problem may be that the idle mixture is set incorrectly or that the
> main
> jet, which sets the high speed mixture in many outboards, was damaged
> when
> cleaned. This can occur if the mechanic did not set the main jet
> actuator
> correctly.
>
> It would be nice to know what was disturbed to limit the possibilities.
> I
> would check the float and needle valve anyway, just to be sure. It does
> not
> sound like a carb cleaner problem at this point.
>
> Mike
> s/v Shanghai'd Summer ('81)
> Nissequogue River, NY
>
>
> From: "R Orkin" <roryorkin at verizon.net>Sent: Thursday, September 04, 2008
> 5:54 PM
>>
>> The carb was cleaned recently but not by me so I dont know if the fuel
>> float
>> is the problem..
>> Where do I look for occluded choke passages and how do I clean them.. ?
>> I was not sure if there was an accelerator pump on this model. Was that
>> a
>> general observation or specific to the outboard.
>> I don't know where an air filter is unless it is right up against the
>> carb
>> behind the air intake
>> Mixture is the most likely culprit but I need to check out some of the
>> other things so I don't try to compensate for another problem with the
>> mixture.
>> There is a real lag between motor trying to pick up the fuel on sudden
>> acceleration..
>> which is why I think it is not the carburator float. A quick turn of the
>> handle leads to immediate stall.
>> It is not burning off the fuel in the bowl then stalling. The valve must
>> be
>> working somewhat or it would not refill at high rpm. If it is in the
>> carb
>> I
>> am thinking fuel residue.. Will a fuel line aditive actually clean
>> anything
>> out ??
>>
>>
>> R22MikeW wrote:
>>>
>>> Rory,
>>>
>>> Since you can get to full throttle (slowly) this rules out problems
>>> related
>>> to supply of air (air filter is OK) and fuel (fuel filter, tank vent,
>>> fuel
>>> pump, etc. are OK) and also ignition. If it stalls on sudden
>>> acceleration,
>>> the problem is either due to too rich a fuel mixture (check for
>>> occluded
>>> choke passages, improper mixture adjustment, improper accelerator pump
>>> action, etc.) or more likely, improper fuel bowl float setting (sudden
>>> acceleration will burn the fuel before it is replaced by the pump.)
>>>
>>> Have you cleaned the carb out recently? If so, did you bend the float
>>> adjustment? The purpose of the fuel bowl is to maintain a fuel
>>> reservoir
>>> for rapid changes in fuel consumption so that the engine is not starved
>>> for
>>> fuel. The float is adjusted so that it maintains a particular level in
>>> the
>>> bowl. It opens and closes a small needle valve in the fuel inlet
>>> line,
>>> regulating the flow into the bowl. Too much and the engine "floods"
>>> with
>>> fuel; too little and the engine runs out of fuel (starves) when rapidly
>>> accelerating.
>>>
>>> Small engine (carbureted) 101 ...
>>>
>>> Mike
>>> s/v Shanghai'd Summer ('81)
>>> Nissequogue River, NY
>>>
>>>
>>> From: "R Orkin" <roryorkin at verizon.net>Sent: Thursday, September 04,
>>> 2008
>>> 4:42 PM
>>>>
>>>> My 9.9 Yamaha has had a variety of starting problems. All seem to be
>>>> fuel
>>>> related. I seem to have it cleaned out to the point it will start but
>>>> still
>>>> have poor response from the throttle. Sudden acceleration will stall
>>>> it..
>>>> slow acceleration is ok and I can get full throttle.. Does this seem
>>>> to
>>>> be
>>>> a
>>>> mixture, fuel pump or other problem to anyone? perhaps automatic
>>>> choke
>>>> issue ??
>>>>
>>>> -----
>>>> Rory Orkin
>>>> Tilghman, Md
>>>> 2000 Recycled Rhodes 22
>>>> Duet ll
>>>> --
>>>> View this message in context:
>>>> http://www.nabble.com/Poor-throttle-response-tp19319533p19319533.html
>>>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>>>
>>>> __________________________________________________
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>>>>
>>>>
>>>
>>> __________________________________________________
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>>>
>>>
>>
>>
>> -----
>> Rory Orkin
>> Tilghman, Md
>> 2000 Recycled Rhodes 22
>> Duet ll
>> --
>> View this message in context:
>> http://www.nabble.com/Poor-throttle-response-tp19319533p19320793.html
>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>
>> __________________________________________________
>> To subscribe/unsubscribe or for help with using the mailing list go to
>> http://www.rhodes22.org/list
>> __________________________________________________
>>
>>
>
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-----
Rory Orkin
Tilghman, Md
2000 Recycled Rhodes 22
Duet ll
--
View this message in context: http://www.nabble.com/Poor-throttle-response-tp19319533p19321799.html
Sent from the Rhodes 22 mailing list archive at Nabble.com.
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