Substation Electrician
New member
I have a 1993 Mercury 175 EFI XRI engine that has a bogging/stumble issue. When the problems first started it would crank good cold off the trailer and ran fine getting out of the hole when leaving the dock. After running and stopping to fish for a bit when I tried to crank the engine it would hit and die. It then would spin over but not fire leaving an oil slick behind the boat. If I use the fast idle it would crank but smoked heavily for a few seconds then I could plane the boat out. At the next stop it would act up again. It finally got to the point where the boat would not plane out even when first unloading and the engine was cold. I carried it to a Mercury mechanic who said the stator was bad and one voltage regulator was bad. The stator and both voltage regulators were replaced and the boat would plane off like it should. There was still a stumble or a bog while getting out of the hole or loading the boat. The cranking issue was still there as well. The mechanic started checking the fuel system and all of the fuel filters were replaced as well as a few lines which were soft. I replaced the fuel line from the dry storage to the engine with new Mercury line and primer bulb. Same issue. I rebuilt the mechanical fuel pump which made a huge difference in the cranking issue but still have the bog/stumble. I talked to the local Mercury dealer who said it sounded like a coil issue. I tested the coils today finding them to all read .1 - .3 ohms on the primary side and 900 - 1000 ohms on the secondary side. The engine was cold. I heated the coils with a hair dryer and re-tested still having .1-.3 ohms primary and the secondary sides all went up over a 1000 ohms with number 5 coil being over 1100 ohms. Does this sound o.k.? Am I dealing with an electrical issue or a fuel issue? I want to have the engine tested at the dealer under load to determine how the engine is performing but they are a month behind. Any help would be appreciated
Scott
Scott