Would a lost Valve Cover Cap cause high revs?

2

2000Penta7.4gi

Recruit
Joined
Jun 27, 2009
Messages
4
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.
 

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maxxman04

Petty Officer 1st Class
Joined
Mar 30, 2009
Messages
352
Re: Would a lost Valve Cover Cap cause high revs?

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

BLinindoll

Seaman
Joined
Sep 16, 2008
Messages
65
Re: Would a lost Valve Cover Cap cause high revs?

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.
 
M

maxxman04

Petty Officer 1st Class
Joined
Mar 30, 2009
Messages
352
Re: Would a lost Valve Cover Cap cause high revs?

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

dontask

Petty Officer 2nd Class
Joined
Apr 5, 2009
Messages
177
Re: Would a lost Valve Cover Cap cause high revs?

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.
 
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