idles up and down then dies

[Gitrdun01]

I have a 95 omc cobra 5.0 50faphub it starts fine idles way up 1400 rpm then slows down to about 900 then will go up and down and eventually die...I changed the throttle pos. Sensor and the iac valve and still same problem. Any ideas on where I should try next?

 

[Don S]

Re: idles up and down then dies

Disconnect the throttle cable and see if the idle settles down. Worn out and out of adjustment cable will cause that problem.

 

[Gitrdun01]

Re: idles up and down then dies

No change with throttle cable disconnected...I just set the engine up and put a new non-marine cap, rotor and wires on it b 4 I became a member now I know bad idea so I switched the cap and wires back to the old ones the idle doesn't race up as high but still the same up and down up and down? I changed from a flat tappet cam to a roller not sure if that would have any effect or not? Also dogging bad was only able to reach 4000 rpm in the water sounded like it was starving for air...loud sucking sound which seems to come and go

 

[Gitrdun01]

Re: idles up and down then dies

Okay after your throttle cable idea I got to looking and noticed some electrical tape on the spring of the throttle body and the spring feels loose. Would this cause the same problem? I guess I assumed electrial because I could'nt see the throttle body moving. but maybe if the spring isn't bringing it fully back?