RoGun_Mako171
Petty Officer 3rd Class
- Joined
- Jun 25, 2018
- Messages
- 79
I purchased a 1989 Mako 171 with a Johnson 88 SPL last July, this is my first boat and my family and I love it. Have been learning a lot about outboards since then and have learned a ton.... replaced plugs (QL77JC4) and wires, rebuilt the carbs, cleaned corrosion from all electronics, replaced the rectifier, replaced the Power head to mid section gasket, fuel lines. I use non-ethanol premium with Quicksilver 2 stroke oil at a 50:1 ratio.
I'm tracking down a problem with white smoke and a bit of a rough idle when slow trolling with an occasional stall, plus a black soot buildup at the waterline on the stern and engine. Runs well at high RPM, max is about 4500. Also, I noticed today that when flushing the engine, there is water spray from the starboard exhaust relief port, but not from the port side. Engine compression is 100psi (port top), 100psi (port bottom), 110psi (starboard top), 110psi (starboard bottom).
I'm thinking the white smoke is possibly caused by a bad head gasket on the port side, however the plugs look good, covered in black oil. Am I on the right track? Also, is it possible to replace the port head gasket without pulling the power head as it looks like I should be able to, or is pulling the power head required?
I'm tracking down a problem with white smoke and a bit of a rough idle when slow trolling with an occasional stall, plus a black soot buildup at the waterline on the stern and engine. Runs well at high RPM, max is about 4500. Also, I noticed today that when flushing the engine, there is water spray from the starboard exhaust relief port, but not from the port side. Engine compression is 100psi (port top), 100psi (port bottom), 110psi (starboard top), 110psi (starboard bottom).
I'm thinking the white smoke is possibly caused by a bad head gasket on the port side, however the plugs look good, covered in black oil. Am I on the right track? Also, is it possible to replace the port head gasket without pulling the power head as it looks like I should be able to, or is pulling the power head required?
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