97 merc 5.7 problems

[Onexl85]

I have a 1997 5.7 merc (serial 0f881527) with an alpha one drive.
Will not idle in neutral, will eventually bog down and shut off. Also will not go over 3000 rpms. Problem started today after a few hours on the water and a few stops.
I can however get it into gear before it stalls reverse and neutral.
Where is a good place to start?
Thanks all!

 

[figaro]

if its carburated ,make sure choke is opening , does it run well up to 3000 rpm , ? hows its state of tune plugs wires filters etc , fuel old /new from a reliable station ?

 

[achris]

I would start with the basics. Do a compression test, check/replace spark plugs, check timing. Replace the fuel filter and check that the fuel tank vent is not clogged. And check (and recheck) you have the spark leads on the right spark plugs.

Chris.......

 

[Maxum88]

carb, fuel filters and the vent tube....

Try starting the boat at the dock with the fuel fill cap off. If you hear a lot of hissing when taking the cap off or it runs fine with it off, your vent line is clogged.

Also, check the mountings on the carb...if the bolts and screws loosen up, you will get a vacuum leak. Check it by using soapy water in a spray bottle. Shoot the base with a stream and check for leaks. Your motor will smooth out for a sec too with mixture temporarily sealing the leak.

-Tim =)

 

[Onexl85]

Will try tonight, should I be starting with a compression test?

 

[achris]

The basics are easy to do, don't take long, cost nothing, and can tell you a lot. That's were I'd be starting.

 

[Onexl85]

Update***

So today I checked a few things, then I played with the idle adjustment screw and got it to settle in neutral. I think what must have happened was As i cut down the engine and it started to shake and shut down, experience told me I wrapped up a rope. So I pulled the drive up to inspect, but never lowered it all the way. that's why I couldn't get over 3000 and plane out. Any way, had the boat up to 34 mph and everything felt good. I do still however have to fine tune the idle. Has anyone every had the idle come out of adjustment?