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-   -   Low full throttle rpms (http://www.mastercraft.com/teamtalk/showthread.php?t=53920)

skiknox 04-26-2013 11:07 PM

Low full throttle rpms
 
95 ps 205 lt1 1:1 acme 541 only getting 3800 at full throttle. Don't have a GPS speed. Pushing on the stick seems fine up to 3000 then I have a lot of room with the throttle but ad as you drop it further rpms and speed just seem not to increase. Almost like the trottle cable isn't pulling like it should

j.mccreight@hotmail.com 04-26-2013 11:14 PM

Something is wrong, you should be pushing close to ~4800rpm @ wot. What was your rpm's before prop swap?

skiknox 04-26-2013 11:23 PM

Boat was need to me last summer and only pushed it to 4000 with stock 13x13 oj. Could it be trottle cable ?

j.mccreight@hotmail.com 04-26-2013 11:31 PM

Maybe, anything is possibly, can you rev it in neutral past 3800, you can disconnect cable from throttle body and have operate throttle body and see if thats your issue.

blackcreek 04-27-2013 10:25 AM

Quote:

Originally Posted by skiknox (Post 929632)
Boat was need to me last summer and only pushed it to 4000 with stock 13x13 oj. Could it be trottle cable ?

Pop off the air cleaner and push the throttle all the way open and you should see the throttle butterflies at perpendicular (90 degrees) or nearly so.
http://i616.photobucket.com/albums/t...1/IMG_0115.jpg


My first guess on an LT1 not getting full power would be fuel pressure. The pump intake screen on the rear passenger side of the motor
tends to clog up if you don't have an inline filter installed before the pump. If the intake screen clogs bad enough it wipes out the pump and you get low fuel pressure. Check the throttle opening and the fuel pressure and if they are good you need to start looking at tps,fuel pressure regulator,clogged injector, ignition,compression etc. Fuel pressure is easily checked at the port on top of the motor. There are a bunch of youtube videos on how to check LT-1 fuel pressure and the indmar lt-1 is the same. Depending on load my 97 205 with the LT-1 pushes at least 45 mph and 4500 rpm on a stock 13x13 prop and the 1 to 1 transmission.

JimN 04-27-2013 10:32 AM

Quote:

Originally Posted by skiknox (Post 929630)
95 ps 205 lt1 1:1 acme 541 only getting 3800 at full throttle. Don't have a GPS speed. Pushing on the stick seems fine up to 3000 then I have a lot of room with the throttle but ad as you drop it further rpms and speed just seem not to increase. Almost like the trottle cable isn't pulling like it should

You should hit 5000 RPM @ WOT- clean the screen and MEASURE the fuel pressure. Don't guess, don't hope.

If you have old fuel filter(s), change now. Also, make sure the fuel pickup tube is clear of debris and the anti-siphon is working properly and make sure the shutoff valve is fully open.

skiknox 04-27-2013 10:49 AM

when I winterized I changed both fuel filters, the one that comes right off the tank and the one on the motor. I will look into checking pressure and check throttle body. thanks everyone for the tips.

skiknox 04-27-2013 10:52 AM

hey JimN where is the shutoff valve located?

Table Rocker 04-27-2013 11:13 AM

Quote:

Originally Posted by skiknox (Post 929706)
hey JimN where is the shutoff valve located?

JimN is offline, so I will answer that one. The fuel shutoff is on top of the fuel tank between the tank fitting and the hose that goes to the 1st filter. It is an aluminum fitting with a short lever on top and the fuel line is attached to it. Move the lever back and forth a few times. In line with the hose is "open" and perpendicular is "closed". See what it feels like. If it doesn't feel like it is working right, it is easy to remove and inspect.

skiknox 04-29-2013 07:33 PM

Well today I was going to pull the fuel pump and check the screen an figured I would put the fake lake in it first. Well lt1 ran full rpm range with me manually actuating trottle body and with the stick. The only thing I did prior to starting is making sure valve on tank was in on pos and it was but turned it in and off and couple of times. I guess I won't fully know until I get it back on the lake but it should run and diff should it?


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