Good job figuring out the new head gasket orientation... I don't know why that line up tab is there, the gaskets looks symmetrical but who knows. It isn't uncommon for these head gaskets to blow out in that area, wish the head gaskets had sealing rings around the cylinders. The engine doesn't look badly overheated, but an overheat oftentimes leads to a warped head and blown gasket. Compression readings are oftentimes inaccurate on these engines due to their tiny combustion chambers. That line running up to the gage can alter the readings due to the added volume. This wouldn't make much difference on a car engine, but can make a big difference on small engines. OK, so it seems like you have decent compression and spark, but that engine is only running on one cylinder. Any signs of water on the plugs? Could be an internal water leak. You mentioned pulling that fuel pump apart, this could be your problem. Those pumps really aren't meant to be disassembled, A leaky diaphragm could be allowing fuel to flood into the cylinder connecting to the fuel pump port. An easy way to check for this issue is to disconnect the fuel line while the engine is running, if RPM picks up after a few seconds (when the fuel in the line/pressure goes away), this is a pretty good indication that the fuel pump is leaking. The only other thing I can think of is if one of the leaf valves is busted/stuck open. Not real hard to pull that intake off this engine quickly to have a look. These really are nice little engines, but are prone to cooling issues when used in salt water. Always check and retorque/tighten the head bolts and exhaust manifold bolts.
My grandfather always had a Johnson 3 on the boat at the cottage. Fond memories!
Good job figuring out the new head gasket orientation... I don't know why that line up tab is there, the gaskets looks symmetrical but who knows. It isn't uncommon for these head gaskets to blow out in that area, wish the head gaskets had sealing rings around the cylinders. The engine doesn't look badly overheated, but an overheat oftentimes leads to a warped head and blown gasket. Compression readings are oftentimes inaccurate on these engines due to their tiny combustion chambers. That line running up to the gage can alter the readings due to the added volume. This wouldn't make much difference on a car engine, but can make a big difference on small engines.
OK, so it seems like you have decent compression and spark, but that engine is only running on one cylinder. Any signs of water on the plugs? Could be an internal water leak. You mentioned pulling that fuel pump apart, this could be your problem. Those pumps really aren't meant to be disassembled, A leaky diaphragm could be allowing fuel to flood into the cylinder connecting to the fuel pump port. An easy way to check for this issue is to disconnect the fuel line while the engine is running, if RPM picks up after a few seconds (when the fuel in the line/pressure goes away), this is a pretty good indication that the fuel pump is leaking.
The only other thing I can think of is if one of the leaf valves is busted/stuck open. Not real hard to pull that intake off this engine quickly to have a look. These really are nice little engines, but are prone to cooling issues when used in salt water. Always check and retorque/tighten the head bolts and exhaust manifold bolts.
Some good tips there, donk. I think I have her running decent, if anything could possibly use some points and better carb clean.
the gasket seems upside down because the orientation tab is not on top to match the tab on the cyl head !!!
The tab at 8:30? Which way is correct? It is running great 7 months later, just came in from a spin.
Little Johnson, lol!