Mercruiser 888 lacks power and backfires

"Ford 302, new distributor &#4

"Ford 302, new distributor (Electronic Prestolite), new carb (Holley 2 BBL), timing is dead on (10 BTDC). Runs like a champ with no load. Put a load on it and it idles out of the harbor fine. Run the throttle up to about 1,000 RPM's (can't go any higher without it cutting out) and it backfires and no power to accelerate?"

"What were the symptoms before

"What were the symptoms before the new dist. & carb? Is there paint or a corrosioon prevention coating on the carb linkages? I had to scrape off some of the paint on the new Mercarb I put on last month due to it causing some drag on the linkages. Made a big difference.

Things to check: Fuel filter inside mech. pump or the pump itself. What is the fuel pressure? New dist.--how about plugs and wires? Without a load, you say it runs like a champ. Do you have quick accel. response from idle RPM above 1,000 rpm? Did you check the timing at an angle or perpendicular to the markings? Angles can give a false reading. What is the timing under a load? When you installed the carb, will the throttle/shifter control allow the carb to go to WOT position? Electric choke working? It needs 12 volts and a ground wire. Good luck."

I had the same problem with a

I had the same problem with a new Prestolite Electronic distributor on my Merc 351. The trouble turned out to be the advance springs looked like they came off a shock absorber. I couldn't get the advance to move beyond 12 deg and the popping began around 2000 RPM. I replaced the springs with springs from the old distributor and the problem has been solved for 5 years.
Check your timing advance with a timing light and you should be reading around 36 deg max @ 3200 RPM with 10 deg inital advance.
Lakeguy

"I have been having sort of th

"I have been having sort of the same problem, I have a Mercruiser 5.7 Litere LX. New Webber 4BBL Carb, Distributer set @ 10 deg BTDC, New Plugs and Wire, New Fuel Pump , Idles good with No Load, Runs Good at about 4200 RPM under Load but after running a good long while and after slowing down motor does not want to get back up over 2000 RPM.and I Hear a Hard Clicking Sound @ 2000 RPM. All Fluids are at good levels, Water Temp about 190 deg. wonder what coud be happenning."

"Gregory: "Hard Clicking

"Gregory: "Hard Clicking Sound @ 2000 RPM"; does it only occur after a hard run; metal on metal tapping noise? May be a collapsing lifter if the sound disappears after the engine is shut down for awhile and then restarted. Is 190 degrees the normal operating temp? Sounds high.

New carb; choke may be binding; painted linkages are a regular problem on carbs. They will bind or stick all of a sudden. Scrape the paint off at the connecting points of the linkages.

Flame arrestor too tight can distort the air horn causing choke and throttle to bind after carb housing expands from engine heat.

Probably not the cause, but what does the cap and rotor look like? White corrosion on the rotor and cap leads and black carbon streaks under the cap--replace both parts.

If it runs good @ 4200 RPMs and then starts acting up after you drastically reduce RPMs and then try to increase RPMs; something is binding in the carb related linkage or throttle plate.

Next time it happens, have someone watch the carb throttle cable to see if it moves all the way.

Good luck. Let us know what you find. Guy"