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Completely stumped

T

tybo784

New member
I have a 1985 mercury 75hp that was running fine when I got it we took it to the lake and it would not stay running in gear my brother thought the idle needed to be adjusted so he started messing with the link and sync without knowing what he was doing turned out to be a bad fuel line now the motor will not start unless the high idle lever is pulled all the way up and even then it’s only sometimes we used a timing light to get it back in time as good as we can tell we did it right it has fuel air spark compression and timing what am I missing
 
tybo784 said:
I’m just looking to get it to run
Click to expand...

If the compression is low, it CAN'T develop the power it was designed for. However, nothing was posted about resetting the carbs to factory settings and if they're not right, it can easily cause a no-start situation and if it does start, it will run like garbage.

Find a manual and set it to spec. If it has low compression after getting it to start, deal with that separately.
 
Re checked
jimn said:
If the compression is low, it CAN'T develop the power it was designed for. However, nothing was posted about resetting the carbs to factory settings and if they're not right, it can easily cause a no-start situation and if it does start, it will run like garbage.

Find a manual and set it to spec. If it has low compression after getting it to start, deal with that separately
Click to expand...
I checked compression again it’s at 145 on 1 &4 and 140 on 2&3 cleaned the carbs still won’t run
 
tybo784 said:
Re checked

I checked compression again it’s at 145 on 1 &4 and 140 on 2&3 cleaned the carbs still won’t run
Click to expand...
It doesn't start on the trailer? Squirt some gas into the carb- if it wants to start, you'll know that it's a fuel problem. Connect a timing light on one of the plug wires while you're doing this- if the light doesn't seem to have a normal rhythm, it could be a problem with spark control, one or more connections or it coild even be a problem with the kill switch/lanyard.

Make sure the battery cable clamps are clean & tight- I know it's annoying to be reminded, but at some point, just about everyone has found the problem at one of these points.
 
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