Abs777

My 6.2 idle is running a little high. It is running 800-900rpm. I looked at the recommendation for that motor and it should be around 600rpm in neutral. How do you adjust the idle speed on these?

Thanks

NHGuy

If it's a carb you back off the screw. If it's injected that's a whole nother thing.

BUP

iTrader: (9)

6.2 what ? and what year ? if you have Mercruiser and OEM stock MPI engine idle speed is non adjustable, it is all dictated by the ECM by input from various sensors on the motor.

Trash

You have a vacuum leak. Check all the hoses and vacuum lines. A small crack in a vacuum hose can cause this.

Sydwayz

iTrader: (1)

You may also have your throttle cable adjusted a bit too much on the throttle body at idle. On the top of the motor, you should see an adjustment on the throw of your cable. There is also adjustments at the bottom of your thottle/shifter assembly.

Engine off: pull the throttle all the way back, remove the flame arrestor, and look at the throttle body/monoblade.
Then, remove the nut holding the throttle cable to the monoblade. If the throttleblade is able to close further with the cable disconnected, your cable needs adjusted.

looseconnection

Could be corrosion on the TPS, engine computer thinking engine is a a different throttle setting than your controls are at.

Abs777

Thanks guys for the info! This is a brand new 6.2 mercruiser attached to a bravo one. It only has 4 hours on the motor, I'll check out the linkage at the throttle body and see how it is set.

I wasn't sure how it would work with the MPI.

Thanks again!

Captain YARRR

Yes these guys are right, the high idle has to be a symptom of something else.

BUP

iTrader: (9)

easy check would be to unhook your throttle cable to see if your correct idle returns if not try to move the throttle arm yourself to see if you can lesson your rpms. Do apply too much force as you do not want to bend anything. Also check your throttle plate to make it is closed or not restricted from returning to the correct idle speed. had no idea the motor was repower as I think your problem is in your throttle cable adjustment or possible new throttle cable needs to be installed. Also when you unhook your throttle cable make sure the movement of it is very easy and moves in full positions. ( Advancement & return)

Trash

Although possible, I think it is unlikely in this situation. If the TPS was corroded throttle response would be erratic for both acceleration and deceleration. I would look at linkage first, then for a vacuum leak. If those fail to cure the problem it could be the TPS.