TOPIC: 1962 Evinrude Starflite V4 motor is surging

Took my somewhat reconditioned boat out for a shake down cruise yesterday. My boat is a 1960 Dorsett El Rey runabout. About 6 months ago I bought a low hours 1962 Evinrude motor from New York, and had it shipped to my home here in California as a replacement for the original motor of the same year, and model #. After taking delivery I rebuilt the carb, fuel pump, distributor, water pump, thermostat, lower unit, and installed new fuel, and water hoses on the power head before mounting on the boat. I also replaced the fuel bulb, hose, and flushed the tank adding fresh fuel/oil mix. When the motor is up to running temperature it becomes hard to start, and runs well for a few seconds then bogs down then revs back up. I believe it is probably a fuel issue rather than electrical. I've disconnected the fuel inlet hose from the carb to check the fuel pump operation, and checked the fuel tank vent hose. There don't seem to be any external fuel leaks, and was wondering if anyone here could suggest any more troubleshooting options, or problems that would cause this condition? Would be grateful for all suggestions, or comments.
Thanks, Mike.

If you pump up the primer bulb does it stay hard? wondering if the needle and seat is leaking and flooding the motor. floats may not be set correctly.

When I was out on the water, and the motor was acting up I squeezed the primer bulb, and it was solid. Will try looking in to the float, needle , and seat as soon as the rain quits here. Thanks for the suggestion.
Mike.

Well, after much grief I found out what the problem was! First, I swapped out the coil, using the one from my old motor as it worked ok before, per your suggestions. Started it up on the flushing attachment, and it was still acting up, would not idle well, and no amount of monkeying with the idle screws helped. Next I removed the carb, took the top off, and blew in the fuel inlet. Air was getting through, but just barely. Next I noticed when I held the top upright so the float would hang down the needle was not dropping with the float. Disassembled the float, and pulled the needle out to find a small sliver of rubber was wedged between the needle and the seat not allowing it to close completely, or open properly. Cleaned it up, and reassembled, and put the carb back on. Started it up again, and the engine immediately started behaving. Launched the next day, it runs like a scalded cat, and idles nicely. Kinda wish it had been the coil, would have saved me the trouble of pulling the carburetor which is a pita with all the hoses etc. You suggestion was the closest to being right, thanks for the contribution,
Mike.

Yeah, that'll do it too! I've had a few in a lifetime of motor fixing, that did something like that. Had a bit of "fluff" stick in one JohnRude needle/seat and it was acting like a check valve, really made the engine run screwy. Glad you found your problem and can finally & fully enjoy the copious fuel consumption that an old V4 can achieve!

Yup, that bit of rubber was keeping the needle from fully opening, yet allowing just enough fuel in to make the engine surge. Time to get out the fishing gear, could really use a fresh salmon dinner. All seems right with the world when the boat is running properly.

Glad to hear she is running well now. I wonder where the sliver came from? I would suggest running or replacing a inline filter as close to the carbs as possible to help prevent more junk from getting into the carbs.

That's what gets me, there is a fuel filter right below the fuel pump that filters incoming fuel before being pumped to the carburetor thru a 14" long fuel hose. The filter is brand new, I guess that bit of rubber came from either the rubber gasket at the fuel pump valves, also new part, or from the fuel hose itself which is new. I did cut the hose to size with a razor knife, and maybe raised that sliver on the inside of the hose, but being new hose I didn't think to flush it out before installing. At any rate I'll let that dog lie for now, hoping there are no more surprises lurking in the fuel system, but I will be packing the tools necessary to pull the carb again if need be, although I'd hate to do that out on the water.

I would bet it came from inside the new line. If you wasn't able to cut the new line with the knife in one pass, I believe the sliver was most likely created then, It happens. Glad you got her figured out. I have 2 different thought processes on where to place a fuel filter. (I really cant say what one is correct) 1st, place as close to the carb. after the pump, to catch any possible contaminates that may come from a failing fuel pump. Or 2nd place, right before the fuel pump to stop any contaminates from getting into, and causing issues at the pump. For me I would rather go with first thought as a failing fuel pump in most cases is most like the last place a contaminate can enter the carbs. I as well would hate to have to pull carb bowls off out on the water and would hope if I had an issue that I could limp it back to shore and take her home for repairs. Just remember if you overthink things like I do and decide to move your fuel filter, you will be cutting your fuel line again and possibly creating a new piece to get stuck. use the primer bulb and pump some fresh fuel through the lines to clear anything from the lines before you reattach it to the carb.

My thoughts exactly about cutting the new hose, never considered that as a potential problem, hadn't had that happen before. Have run a little over 6 gals of gas through the motor when I last launched with no problems, and am launching tomorrow in the bay for a retest, and a little fishing. I never had that problem with my old motor after thousands of hours of use, a few more bay trips to make sure everything is running ok before going to the ocean, not a good place for breakdowns.