F26 with a Mercruiser 228 Running issue

akwalker · Post by **akwalker** » Sun Aug 14, 2011 2:20 pm

Having a bit of a problem with the engine above. Engine starts and idles fine. Will run at throttle fine for about an hour. After a run, and then an extended trip at no wake speed, the engine will not reach operating RPM, misses, smells of exhaust and has no power over 3000 RPM. I have rebuilt the carb, changed the fuel/water separator and added an additional inline fuel filter. I get the same result. Previous owner had changed from points/condenser to Pertronix electronic ignition. I'm thinking that there is a prblem with it. The engine acts just like the timing is not advancing. If we sit at the dock or at anchor for an hour or so, it'll at normal again. I really don't think its a fuel delivery problem. Any ideas?

BTW, coil is new, plugs and wires are new.

Thanks!

randyp · Post by **randyp** » Sun Aug 14, 2011 4:08 pm

If you're sure it's not a fuel delivery issue then I think you're on the right track with the ignition. Just to be sure check you in-line filter screen to see if you have any gunk in it. Could also be coming from the bottom of the gas tank if it's the original galvanized tank.

akwalker · Post by **akwalker** » Sun Aug 14, 2011 4:36 pm

randyp wrote:If you're sure it's not a fuel delivery issue then I think you're on the right track with the ignition. Just to be sure check you in-line filter screen to see if you have any gunk in it. Could also be coming from the bottom of the gas tank if it's the original galvanized tank.

I pulled the pickup tube from the tank last week and it was clean. The check valve in the line was working as well. Its strange to me that it only happens when the engine has run for about an hour, and, like I aid, it seems like it is loosing the spark advance. I would like to go back to points and condenser, but whoever did the electronic conversion disposed of the original breaker plate. I have to find one of those.

Big D · Post by **Big D** » Sun Aug 14, 2011 5:42 pm

When you turn the rotor by hand then let go, it should spring all the way back by itself. If it doesn't, it's sticking and you may not be getting full advance. Also, the electronic kits require a full 12 volts to operate properly so if your engine originally had a ballast resistor, ensure that it has been bypassed and check the voltage going to the sensor.

Big D · Post by **Big D** » Sun Aug 14, 2011 5:47 pm

Check your tank's vent to make sure it is not clogged with anything. Check the vent and the hose. The hose should be going downhill from the vent to the tank. prefferably with an upward loop at the vent. When this happens again, you could try removing your gas cap. If the engine picks up, then chances are it's a vent issue. The other thing you can do to eliminate the ship's fuel supply system/hardware and fuel is to hook up a portable fuel tank right to the engine. If the issue does not occur during a test run, the problem is before the engine.

prowlersfish · Post by **prowlersfish** » Sun Aug 14, 2011 6:15 pm

Fuel filter in carb , fuel pump ??

akwalker · Post by **akwalker** » Sun Aug 14, 2011 6:34 pm

Thanks for the replies. No ballast resistor or wire, full 12 VDC going to the coil. The first time this happened, I did remove the fuel fill cap, with no change. Fuel filter in carb is new. The thing that puzzles me is the exhaust smell. It does not smell like raw fuel, it smells like heavy burnt exhaust. When I try to advance the throttle past 3000 RPM, she falls on her face.
I'm going to try and find a breaker plate for the distributer, and go back to conventional ignition. So far, no luck finding the part online.

Big D · Post by **Big D** » Sun Aug 14, 2011 7:04 pm

Timing set to spec? How old is the fuel?

akwalker · Post by **akwalker** » Sun Aug 14, 2011 7:11 pm

Big D wrote:Timing set to spec? How old is the fuel?

Am going to recheck timing tomorrow. Fuel is not that old, a few weeks, and supposidly ethynol free. If it was bad fuel, I would think that it would run poorly all the time, not just after an hour?

Big D · Post by **Big D** » Sun Aug 14, 2011 10:10 pm

Have had old fuel do funny things. Just thought it worth eliminating as a possibility; the more info the better. Use the portable fuel tank, it's a great tool to set your mind at ease and steer you in the right direction.

prowlersfish · Post by **prowlersfish** » Sun Aug 14, 2011 10:28 pm

If you have to run it over a hour a portable tank won't help much you will run out of fuel first .

Big D · Post by **Big D** » Sun Aug 14, 2011 10:48 pm

How about running for an hour, then switching it over and carrying on?!!

Coil replaced with internal resistance coil right?

vabeach1234 · Post by **vabeach1234** » Mon Aug 15, 2011 6:01 am

Before my engine replacement I tried two of those pertronix ignition kits and had similar symptoms that you are encountering. The engine would run fine at idle but not turn above 3000 rpm. Ended up going back to the original points and condensers and ran like it should. I have the chrysler 318 though. When I had my new engine installed I had an MSD installed to help with fuel economy and that eliminated the condenser but not the rest of the innards of the distributer. You may have to get a whole new electronic distributer if you can't find the parts for your current one.

koviak · Post by **koviak** » Mon Aug 15, 2011 8:22 am

I also had issues with the electronic dist. Pick ups would get hot and stop working or short out. Changed to Mallory and issue went away.