My 1973 85 HP Won't Start!

[MainstreetUSA1]

I have a1973 85 HP 4-cyl. mercury. Carbs just gone through, has tons of spark on all 4, has 120 PSI compression on all 4. Won't start even when you spray a shot of fuel through the carbs or down into the cylinder before starting. Timing is set, is this a reed valve problem? Any help will be greatly appreciated!<br />Thanks!

 

[Ben Konopacky]

Re: My 1973 85 HP Won't Start!

Is this a new o.b. to you ? how and when did this engine run the last time? how old is the fuel? How long of a spark ? all these ? might bring a solution,from what your saying it should start.where is the trottle when starting eng.,are you choking it and are the plugs wet..answers please.

 

[Chris1956]

Re: My 1973 85 HP Won't Start!

MainstreetUSA1 - You can test the reed valves for function by placing your hand over the carb throats and cranking the engine. If they are good you will feel suction. However, I think you chould check the timing of the spark. If the compression and spark are good, and you are spraying fuel in to the carb throat, it should at least pop, if not run for a few seconds. Are the spark plugs good, are they making a good ground to the block? Also, when you spray fuel into the cylinder, you have taken the reed valves out of the picture. The motor will pop even if they are bad. It would seem to be spark related! Are you getting water into the cylinders? That would kill the spark.

 

[MainstreetUSA1]

Re: My 1973 85 HP Won't Start!

Thanks for your replies! Here is some more info...The motor is new to me the previous owner said it sat for about ten years. I have fresh gas. When I try to start it and choke the engine the plugs aren't getting wet. Also the is good spark across the end of the plug. When I put my palm over the carb throat there is very minimal suction that I can feel, yet there is good compression. Any more help would be greatly appreciated!<br /><br />Thanks!

 

[Ben Konopacky]

Re: My 1973 85 HP Won't Start!

Are you checking for spark with a spark plug checker w/plugs seated or removed or are you looking for spark across the perma gap plug ? when cranking eng.,w/key check dc v of white wire on switch box (starboard side)meter R lead on W term., meter B lead to a good ground you should have min. 9.5 v dc while cranking,if not ,could be low/bad batt.<br /> Good luck

 

[Hank 911]

Re: My 1973 85 HP Won't Start!

These old inline motors are famous for being hard to start when cold. Two things are needed; 1 HOT battery that will really spin the daylights out of it 2 -and this is the key- pump the bulb and crank on full choke til it starts. Leave the cold start throttle about 1/3 open.When you think it's flooded it's just getting ready to start. If your plugs are not wet there is no way it is gonna start. There is a good thread on this titled "I hooked up the fuel line,turned the key and guess what". I'm bumping it to the top. It applies your motor and most all inlines. I've owned an 1150, 850, and 75hp inline and they all had to be started this way. Note the postings by Clams Canino he won't steer you wrong. Hope this helps.