200xs throttle butterfly

[MadMat]

Is there any reason why the throttle butterfly should not fully open on a 200XS motor? On full throttle, the throttle stop prevents the butterfly from being quite fully open, perhaps only by 1/4 -1/8". The mechanic has said this is correctly adjusted, however I cannot understand why the throttle butterfly should be anything other than fully open, so it's parallel to the airflow. Have I missed a trick here?
Thanks
Matt

[hsbob]

will check mine this week end and the merc manual. let you know tuesday.

[hsbob]

did check this week end. on a scale of 1 to 100 i would say mine is at 97 or 98% full open. this is looking down the intake at the air butterfly.

[MadMat]

Thanks hsbob!!! :D

[MadMat]

OK, we've completed our first full race with the new motor - but only just.
Motor wouldn't restart after the finish due to a flat battery. Is there a known charging problem with these motors? We started losing the motor towards the end of the race every time we used the trim or lifter, it would shutdown. Doing a bit of research, it seems the guys in europe are using huge batteries with them, otherwise the batteries go flat. With the motor running, we were seeing 14+ volts, so it's clear the alternator is pushing out juice, but perhaps not enough to charge the battery with extensive use of the trim & lifters? Seems odd. :confused:

[MadMat]

A bit of in race action. Very rough conditions. :)
http://www.mattyorke.com/gallery/albums/ramsgate05/IMG_1506.jpg

[staylor]

....and I suspect it's more the factory tolerances then anything else. I just set the linkages on my 150 Opti and the manual stated that a .02 feeler gage should just fit into the stop at full throttle. When set to this value the butterfly was fully open; if it opened to the stop it would be starting to close from overtravel. Last week I set the linkage on a smaller merc and found the butterfly only opened about 95% when it hit the stop. In any event, the motors where I modified the stop for full opening never showed a measureable speed improvement if the butterfly was opened to within an eighth inch of full. As long as it opens enough so that it's within one half the diameter of the support shaft it's OK. This means within 1/8 inch of full open for a 1/4 inch diameter shaft.
Doug

[hsbob]

finally got to the manual. it says to adjust to full open. however the you need to have 0.020 between the actutor and butter fly lever. thus my 98% open seams about right according to the manual. the charging system should put out 60 amps, so your probably correct on using the trim too much. there are rechargable Li batteries out there some where. the army uses them for high power/time applications. their not cheap, but that racing.

[MadMat]

Since we're not the only team with this issue, we're wondering whether the FI system is a greedy git for power, which combined with extensive use of trim & lifters might cause the battery to wear down.
Is the alternator machine or remote sensed? If it's remote sensed we might be able to to trick it into modifying the charging curve slightly. While the peak output of the alternator won't increase, if we can force it to increase it's output even while the battery is fairly well charged this will slow the decay rate enough.
Otherwise, we could have 2 batteries and run the engine off 1 and the pumps off the other with a split charging diode, or perhaps a digital battery to battery charger between the 2.
The problem will be that since it's a race motor we're not allowed to modify it and I suspect that will include the alternator. :(

[hsbob]

your right the DFI uses a blower that probably consumes a medium amount of power.


powers = power. i would add any switching circuites, its just something to go wrong. as you probaly know in racing if it can go wrong it will. you might want to have a manual switching system or a starter like relay[continiuos duty] to switch between batteries. i would suggest the manual switch which can be either and both. batteries will recover if you relax the load so if you switch batteries and then use both at the end you'll have added power to finish.

good luck.