Gt-40 won't rev out

[brad]

i have a 01 gt-40 that won't rev past about 3600 rpm i have checked all the basics plugs leads fuel filter etc does anybody know what it could be

cheers

[M3Fan]

RE: Gt-40 won

You could start by making sure the throttle plate is physically opening all the way.

[brad]

RE: Gt-40 won

I have checked that already

[AirTool]

RE: Gt-40 won

If it has a distributor cap, take it off and clean off all the little metal "fuzzies" by blowing it out with dry air.

AirTool

[MNSuperAir]

RE: Gt-40 won

I had a similar prob and it was a cracked spark plug. At low rpm it could pass enough current but at WOT no go. I am pretty sure I broke it with the extension on my spark plug socket. It tends to pry on the manifolds.

[MNSuperAir]

RE: Gt-40 won

I had a similar prob and it was a cracked spark plug. At low rpm it could pass enough current but at WOT no go. I am pretty sure I broke it with the extension on my spark plug socket. It tends to pry on the manifolds.

[DanielC]

RE: Gt-40 won

Have you checked the fuel pressure?

[brad]

I have checked the plugs and they are all ok....fuel pressure is there a way to check this and what should it be

[DanielC]

Do this:
http://planetnautique.com/index.php?...=fuel+pressure

[brad]

checked the fuel pressure and timing today all seems ok, had another look at the plugs today two on the drivers side were a bit black any ideas anyone

cheers brad

[DanielC]

That is an important clue. You might have a possible problem with the fuel injectors on the different two cylinders.
You can download the GT-40 service manual from this site. It is a large pdf file, but worth the long wait, even if you have dial up computer connections. Another option for getting it is to go to a library with a high speed internet connection, and download it on a "thumb" drive.

[DanielC]

I just looked at the GT-40 service manual I down loaded, and the fuel injectors use a "bank" fire system. Four of them fire each 360 degrees of crankshaft, and the other four fire the next 360 degrees. If four plugs were different, I would suspect the problem is in the computer controls for the fuel injectors. In your case, I would think you might have an injector issue.
It is also possible to have some ignition problems.
Two years ago my GT-40 started to have a random miss sometimes under load, and it just did not have a smooth sound near max rpm. My solution, replace the spark plugs, spark plug wires, distributor cap, and the rotor. I know that is "just throwing new parts at it until it runs better", method of engine diagnosis, but to get an ignition scope hooked up to the engine and run the engine under load, on the river, would of cost much more than the retail cost of the parts I bought to "throw at it"

[brad]

Thanks heaps for your help guys the injectors are being cleaned today and i will test it out this afternoon....so fingers crossed it all works out

[brad]

Found out what the problem is. it turns out the lifters on no1 and no2 were a bit dodgy so after replacing them all should be ok

[DanielC]

What do you mean by "a bit dodgy" ? I do not speak fluent Australian. What were you using for oil?