Would a lost Valve Cover Cap cause high revs?

[2000Penta7.4gi]

We recently blow off our valve cover cap and oil shoot out the opening. The engine also reved up to about 5K rpms with the throttle level all the way down.

Would lack of pressue in the value cover area cause high revs?

Attached is a picture of the cap that blew off.

thanks.

[WizeOne]

Short answer, NO!

[maxxman04]

high revs could be caused by a number of things. incorrect idle adjustment, vacuum leak, timing advanced (tho not 5k rpm's), throttle cable issues.

[BLinindoll]

yeah... 5K is a big vacuum leak, lol. obviously somehow the engine is getting to much air. i would check the throttle cable going into the TB. take the spark arrestor off with the engine off. Are the throttle plates open when the throttle is all the way back? if not, air is entering the motor another way, and a lot of it. not even sure where i would begin to look for a vacuum leak of that size, lol.

[maxxman04]

that big of vacuum leak is generally intake manifold gasket, somewhere. or carb/throttle body mounting gasket.

[dontask]

Why don't you answer your own question on the valve cover cap causing high rpm's by putting on and off and see if the jump in rpm's happens at the same time---each and every time. Then you won't have to weed through some of these answers.