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86 150 stumple - Johnson

W

wtp

Member
I had a whole bunch of problems with this 150. Long story short I tore the whole motor down and put all new power head gaskets in. New carb kits and jets. New valves below the carbs (can't remember what there called) New coils, power packs and stator. New voltage regultor and also plugs. Everything is OEM except stator and power packs. Reed valves are better then what the manual says is acceptable. Compression is good. Runs great at anything over idle. Seems to idle good but take off stumbles alittle. Sometimes it stumbles just for a second or two and planes right out. sometimes it will stumble for 4 to 6 sec and takes right off. It's weird but runs great at mid and top end. I know your gonna ask so I'll tell you. I've been through these carbs a total of 5 times. Every hole is spotless. jets are new. carb floats are set to level when held up side down and 7/8 drop when turned over. VRO has been removed and 2 pumps installed. All new fuel lines. New primer bulb. I'm not completly certain but I think the link n sync is right. Starts good, runs good but just that darn take off. Running QL16V plugs. Was told to try have the timing advance a couple degrees before the throttle plates start to open. That did nothing and is why I'm thinking fuel. Out of ideas.
 
were the fuel pumps you installed the type like on the mtrs that were built before VRO. You know with the filter screen rite their with the big screw at the fuel inlet? I ask this because i had a mtr rebuilt that had VRO and told the mech; to remove the VRO that i wanted to go back to mixing oil. the pump he installed looked exactly like that monster VRO PUMP except it didn't have a port for the oil, that pump failed 1 month after rebuild and i went to every marine dealer [years ago] in the tidewater area looking for it, they kept trying to hand me a full VRO pump even though i had the other pump in my hand. Finally went to rons marine in portsmouth and he spotted it from across the room brought me another at $155 told me that the pump was under warantee and can probably get me my money back, that he did. Put the new pump on and mtr ran like a champ. You say your problem may be fuel, check into your pump change out. just a thought.
 
would it hurt anything if I tried it with only one fuel pump. Right now i'm running 2 pumps like whats on the 1983 150hp
 
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