View Full Version : 92 Prostar 190 with 351 running rough question
92 190 PS
04-27-2013, 04:32 PM
92 Prostar with a 351 HO that I'm getting out for the first time this spring. Worked on it yesterday changing fluids and running in driveway and everything was great. Ran it for 15 minutes or so to get it up to temperature and again when I was done and everything worked well.
Today before changing plugs and doing a couple more finishing touches it is not running well. Starts quickly and runs as long as you give it gas. If you try to hold any RPM or idle it won't stay running. Pulled the fuel filter in the tank (On the end of the fuel line) and cleaned it. Changed the plugs and still no progress.
Looking for the next things I should check?
04-27-2013, 06:28 PM
Still running the original mechanical fuel pump?
Maybe the diaphragm let go ...... Any exhaust details? Whitish smoke?
92 190 PS
04-27-2013, 09:44 PM
Yes still the original fuel pump. Any simple way to check the diaphragm?
As for smoke, don't notice anything out of the ordinary.
04-27-2013, 11:15 PM
Start with the basics:
New plugs are good....gapped correctly?
Points or electronic ignition?
What is the age and condition of the distributor cap and rotor?
Same goes for the spark plug wires.
What is the idle speed set at?
Is your electric choke fully open after about a minute?
How much old fuel in the tank and was it treated when you winterized?
Is timing correct?
Has the carb ever been rebuilt? Is it a 4160 or a 4010?
Once you get through that, I would look for a vacuum leak. Spray carb cleaner around the base of the carb with the engine running (use caution here as it's flammable). If your engine speeds up with the carb cleaner, you found your leak.
That should keep you busy for a while:rolleyes:
92 190 PS
04-29-2013, 08:49 AM
Just an update for anyone that has similar issues in the future.
Pulled the fuel filter out of the bowl on the fuel pump and replaced it. Pulled the two inlet tubes off the carb and flushed them. Sprayed some carb cleaner in through the carb a couple of times.
Re installed everything and now the boat runs great again. Guessing there was some dirt in the lines somewhere. Hoping to run the fuel I have in the boat ASAP and start with a fresh tank for spring.