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Thomas1966
06-24-2009, 03:52 PM
I have a 1993 prostar 205 with a 351 engine. Boat idle changes from 700 to 950 rpm's. Upon accelaration boat runs fine no problems, I have changed the fuel/water seperator, but that did not clear up my problem. Another friend thinks my backpressure could not be correct, which means I may need a new muffler. Does anyone have any suggestions?

GuitsBoy
06-24-2009, 04:23 PM
You can spray carb cleaner around the intake and carb to see if you have a vacuum leak, but more likely than not you just need to have the carb rebuilt. If youve still got the stock holley 4010, you way want to upgrade to the 4160 now. Its a much easier carb to tune and performs better on this motor.

mcmx2
06-24-2009, 04:55 PM
My guess is that a power valve is out on your carb.

TMCNo1
06-24-2009, 05:29 PM
My guess is that a power valve is out on your carb.

I agree, went through the same thing last fall.

flat broke
06-24-2009, 07:42 PM
hey harold,

I have a 89 ps 190 351 1:1 how do I tell if I have a 4010 or a 4160 ? and what is the difference ? any info would be great thank you

TMCNo1
06-24-2009, 07:51 PM
hey harold,

I have a 89 ps 190 351 1:1 how do I tell if I have a 4010 or a 4160 ? and what is the difference ? any info would be great thank you
It should have a 4160 from the factory, unless a previous owner has changed it out.
4160 is single inlet fuel line @45 degrees on front bowl, port side,
48688
4010 is dual line feed with inlets on front and rear bowls starboard side, with externally adjustable floats and side fuel level sight holes,
48689

flat broke
06-24-2009, 09:01 PM
It should have a 4160 from the factory, unless a previous owner has changed it out.
4160 is single inlet fuel line @45 degrees on front bowl, port side,
48688
4010 is dual line feed with inlets on front and rear bowls starboard side, with externally adjustable floats and side fuel level sight holes,
48689

looks like I am good to go thanks for the reply and the great tech info :)

GuitsBoy
06-25-2009, 08:28 AM
Why did MC change to the 4010 on later models anyway? Was it supposed to be a higher performance option? It has adjustable floats, dual fuel feeds and dogleg boosters, etc.

TMCNo1
06-25-2009, 12:37 PM
Why did MC change to the 4010 on later models anyway? Was it supposed to be a higher performance option? It has adjustable floats, dual fuel feeds and dogleg boosters, etc.
Apparently it was the decision of Indmar to use the 4010 on the 351 HO with GT40 heads that put out 285 HP.

GuitsBoy
06-25-2009, 12:42 PM
Apparently it was the decision of Indmar to use the 4010 on the 351 HO with GT40 heads that put out 285 HP.
Are there real world improvements over the 4160? So many of us have swapped out our 4010s for the 4160's. Im just wondering if were actually taking a step backwards.

Thomas1966
07-06-2009, 11:05 AM
You can spray carb cleaner around the intake and carb to see if you have a vacuum leak, but more likely than not you just need to have the carb rebuilt. If youve still got the stock holley 4010, you way want to upgrade to the 4160 now. Its a much easier carb to tune and performs better on this motor. Thanks for the help, Carb was the problem

Thomas1966
07-06-2009, 11:06 AM
thanks for the info, carb was the problem

GuitsBoy
07-06-2009, 11:53 AM
Thanks for the help, Carb was the problem

Glad you got it sorted out. What was it specifically? And intake leak? Just needed a rebuild?

TMCNo1
07-06-2009, 01:23 PM
Glad you got it sorted out. What was it specifically? And intake leak? Just needed a rebuild?


Yea, just curious as to what the cure was for others who may experience the same problem.