Hands around carb intake and it revs up????

[dbmstr124]

I have a 1996 Renken 19 footer with a vortech V6 mercruiser. I put new head gaskets in it. The boat ran great for weeks. I took it out, pulling tubers. The last one got on and when I went to run the boat it didn't start, just cranked. It sounded like it threw timing. After being stranded for 6 hours beached on an island I used a screw driver to hold the intake valve on the carb (choke) half way closed, to limp home. I put new spark plug wires on it cause the coil wire was arcing. The boat now fires up, I re-timed it. It runs great at high RPMS. If I try and make it idle I can't get it to unless its very high or the carb is half way choked. I put my hands over the carb and it runs great. Vacuum leak? Thanks for all your help.

 

[Anchor Management 1]

Re: Hands around carb intake and it revs up????

Could be a Vacuum leak ,But what it wants is more fuel,Try to get it to idle and spray some carb cleaner any where there could be a vacuum leak and see if it idles good, if so fix the leak.

 

[dbmstr124]

Re: Hands around carb intake and it revs up????

Thanks I'll give that a shot. If not is there anything else it could be? Thanks again.

 

[180shabah]

Re: Hands around carb intake and it revs up????

Vacuum leak is a good place to start, since everything was just apart.

Also, try adjust the idle mixture. Or it could just be time for a carb rebuild.

 

[dbmstr124]

Re: Hands around carb intake and it revs up????

Well here I go. I'll check for the vacuum leaks first, then go for the carb. Thanks for all your help. I'll let ya know what I find.

 

[rbh]

Re: Hands around carb intake and it revs up????

have you tried the wd40 trick were you spray it around your carb base gasket? if the motor picks up theres your leak, try around other parts of the carb and the top of the head to see if you have any other places it leaks air.
rob

 

[dbmstr124]

Re: Hands around carb intake and it revs up????

Yes I did that and found a couple leaks. I pulled the carb off, cleaned it, I sealed all around the intake manifold as well, which is where I found the leak. I had to pull the distributor in order to get to the back. I did not spin it. I then put it back together and it was back firing, not actually trying to start. I pulled the number 1 plug, brought up the piston to TDC. Pulled the dist cap, ensured its at number 1, and I'm still back firing out of the exhaust on the outdrive? I've had this happen before and usually doing the procedure I just discussed gets the timing close enough to start and time. Any ideas? Could it be 180 degrees out? Thanks guys and gals.

 

[bruceb58]

Re: Hands around carb intake and it revs up????

Did you check the timing?

 

[dbmstr124]

Re: Hands around carb intake and it revs up????

It wont fire to check the timing. Usually by bring it TDC and setting the dist I can get it close enough to start then I time it. Now it wont start...I'm sure its timing, but does it sound like its 180 degrees out, or should I just keep tweeking it until she fires?

 

[180shabah]

Re: Hands around carb intake and it revs up????

Certainly could be out 180*, When you brought #1 to TDC did you hold you finger n the plug hole to feel for air pressure?

Easy enough to check and correct if needed.

 

[capecodder116]

Re: Hands around carb intake and it revs up????

You might be on exhaust stroke....not compression stroke...