old air cooled mariner

[lark2004]

Hi, I have an old air cooled mariner 3.5hp.<br />Does any one have any ideas as to what whould cause the rpms to drop as the engine warms up?

 

[lark2004]

Re: old air cooled mariner

^

 

[phatmanmike]

Re: old air cooled mariner

improperly mixed oil ratio. remember, its air cooled, which means that the oil mix is VERY VERY important, much more precise than a water cooled motor. <br /><br />my sea kings are very touchy about that. they are both air cooled.<br /><br />how old is it? a lot of these older air cooled motors need to be mixed at 24:1 or 32:1 try 24:1 and see if it improves....<br /><br />also, try posting model and serial numbers

 

[lark2004]

Re: old air cooled mariner

nah, already run 25:1 oil ratio, will let you know of model numbers soon. What about timing? I know that on my 40hp engine the timing shifts with the throttle, but on the 3.5 it is fixed. Any ideas?