1973 Mercury 75 very hard to start cold

PwrStrkd73

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Mar 20, 2008
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Hi All, New to this forum, but it looks like a very good site! My wife and I recently was given a fishing boat and a Mercury 7.5 Hp outboard by her stepdad. I helped him put a new water pump in this engine 3 or so years ago and we took it out for a couple of hours on the river. Then we were going to start working on the hard starting issue, but never got around to it and the motor hasn't been started since.

The problem is that it is a real nightmare to start! You can try to start it using ether (starting fluid), full choke, no choke, or whatever and it takes forever to start. Once it does start though it will fire right back up after you shut it down as long as it hasn't cooled down for more than 2 or 3 hours. I believe the only thing that helps it start cold is having it in gear or maybe keeping it at full throttle (sorry it's been too long for me to remember exactly how we did it). The fuel line and primer bulb are new, and he also replaced the sparkplugs, but I think that's all he did in his attempts to get it starting properly.

Any suggestions on what to check or replace would be appreciated.
 

Laddies

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Sep 10, 2004
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Re: 1973 Mercury 75 very hard to start cold

Don't use starter fluid on a 2 cycle you will ruin it. You either have a choke that is not operating right, some had a 2 piece butterfly, the the spring gets weak on or breaks so when the engine is cranked 1/2 on the butterfly stays open and the choke don't work or the carb needs to be cleaned.
 

PwrStrkd73

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Mar 20, 2008
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Re: 1973 Mercury 75 very hard to start cold

OK, so either of those problems will make it hard to start cold, but run fine and restart when warm OK?
 
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