Tohatsu wont start in idle

[sillywilly]

1986 tohatsu 70hp starts full throttle but not idle. Will stall out mid throttle. Carb clean, filter clean gas line ok. What next? Any help greatly appreciated.

 

[pvanv]

Diagnose. What is your actual model: M70A? When did this problem start? What method did you use to clean the carbs? Is the float height OK? What do the plugs look like? What testing have you done to the mechanical and ignition systems?

 

[sillywilly]

Model is M70A2. I have replaced fuel tank, fuel lines, fuel pump, battery, battery cables, starter, and spark plugs. I have completly disassembled the carberators excet for adjustment screw and thoroughly sprayed every part and cleaned with a needle. Tried blowing past float needles with mouth and couldnt. The throttle and choke work when engaged. The problem started randomly one morning, it was having flooding issuse so i replaced the fuel pump and it ran like a top for one day and the next morning it would only start at full throttle. Plugs are both getting good spark. when not at full throttle it will back fire and sputter like it wants to start but bogs down after 3-4 sputters.

 

[pvanv]

Sounds like the low-speed carb circuits are restricted. The fuel pump did not fix flooding; That problem lies in the carbs. NEVER push anything through carb passages, as it is likely to cause scratching, which leads to weird mixtures. The starter has absolutely nothing to do with that issue. If you did not give the carbs a 4-plus-hour soak in real carb dip, followed by a liberal blow-out with generic carb spray, that needs to be done, after complete disassembly, including the pilot screw, jets, emulsion tube nozzle, etc. When preparing to pull the pilot screw, gently seat it first, counting the precise number of turns, and when reassembling, set it to the same number of turns.