I’ve been fighting this problem for 6 mons…
Motor runs good and runs strong going 50 - 60 miles straight offshore. After a long run and it sits for a few mins. ( 30 to 45 mins ) it doesn’t want to run at all. It’ll cough - spit and sputter until it finally gets going. Doesn’t want to run a smooth trolling speed ( 5 to 8 mph )after a long run. It always starts right up but doesn’t want to stay running until you baby it for a few mins…everytime you stop it’ll do it after the long trip out. You can run it all day at the lake or inshore back and forth and it does great but run it WOT ± for a couple hrs - then let it sit and you’ll need patience.
I’ve replaced all fuel lines from the tank to the motor - new fuel filters - new primer bulb ( twice ) - new water separator - vac. lines - used a isolation fuel tank to isolate problem on the motor side - new fuel pump - de-carbed - new plugs and wires ( twice ) - checked and tested power pack, compression, coils - all checked within manufactures specs. Double and triple checked for air leaks on all hoses and lines. Checked for dirty fuel.
It acts like a car motor thats over heating. When a car motor is running hot and you stop it’ll get hotter for a while before it starts to cool. You can’t start it when it’s overheating…this motor acts the same way. Could this be a temp. problem…?
I haven’t checked or replaced the t-stats and I haven’t had the carbs rebuilt either. I’ve had two spun props on this motor in the last 2 mons. - someone told me once that extreme exhaust temps will can cause a spun prop. There are no high temp. indicator lights coming on - all indicator lights look good.
Any ideas on this problem will be appreciated…