[rich-flanders18]

Hi,

I have a mercury 1974 850 (85hp) thunderbolt ignition outboard. Its a complete pain to start when cold, fires 4/5 attempt and on really cold days many more attempts. As you can imagine im totally fed up now. My neighbours think the boat is call "start you bastard"! To rectify the problem i have done the following;
-New fuel lines and bulb
-carb strip and rebuild with new parts inc float set up.
-Full timing set up and sync.
-adjusted the choke butterflies.
-new fuel pump.
-full electrical check all good.
-compression is great on each cylinder.

Once she runs she is good for the rest of the day. except when the sea temp is <7'c and been off for an hour or more. Starting her that day after a fishing trip involved a few squirts of mixed fuel into the carbs, a prayer to the big man and getting everyone on board to shout "start you bastard" at the engine!...And she did thankfully!

That reminds me to mention, she starts first time with a shot of fuel in the carbs but is a nightmare to do when out on the water as you have to lay on the bathing platform with the blood rushing to your head and ive nearly lost the wrap around twice now!... plus the missus thinks its funny to shove ice in the back of your shorts while your busy getting the engine sorted!..Got to love her though!

Anyway i have been doing some more research on this and im finding that people have converted their engines with the same issues to primer solenoids instead of butterfly shutters with great success!!! I just cant find a DIY set of instructions for the conversion though. I think this will work with my motor as it starts no problems with a shot of gas into the carbs but struggles on the choke shutters.

Now the questions are....
1)Can this conversion be done with my motor?
2)what will i need?
3) How do i do it? and where would the fuel have to be injected/squirted into...? the mouth of the carbs or would i have to make away of getting the fuel directly into the manifold behind the butterflies in the carbs??

It would be nice just to turn the key and go with out any hassle or worries of will she get me home!

Thanks for reading my post and any help would be greatly appreciated!

Regards,


Richard

[Chris1956]

Rich, There may be a way to improve your starting procedure, without modifying the motor. Pump the primer up hard, and then force some extra fuel, past the inlet needles. You will slightly flood the carbs, like on the english motorcycles that had "ticklers". "Ticklers", in case you don't know were little push buttons on the carb that sunk the float, allowing the carb to flood.

Now hold the choke button down and crank the motor, cold start lever all the way up. This should help a bit.

[Laddies]

I don't see why it wouldn't work here's a drawing of the way it works you should check your engine and make sure. As there are quite a few of the inline 6s around that hane died so you should be able to find a donor to save some money.

[Chris1956]

Laddies, That diagram is very cool. It appears that he would need a 4 way brass fitting to replace the center balance hose fitting, and drill thru the carb bowl, where the choke plates used to attach. He could then attach the solenoid.

It does appear that the top crankcase fitting would not get any fuel from the enrichener circuit since it is above the top carb bowl level. Is that true? He probably has a dissy on his motor. It appears that is where the solenoid bolts on. Is that an issue?

[Laddies]

Chris, mercury has a fitting available that has same threads a the plug for the high speed jet And yes I think on cranking very little fuel goes to the upper crankcase just as does't on the 6 cyl. but when the bottom 2 fire the increace in RPM will draw it up.