2001 Mercury 8.0 HP won't start

[eggy123]

Hi,
Any help would be appreciated!

I just got a 2001 mercury outboard, 8 HP 2 stroke, manual start w/tiller.

I ran it for about an hour and it ran fine. when i tried to start it, it would not start again. Since then I have checked for spark, it has new plugs and both get good spark. I have replaced all of the fuel w new fuel and oil. I have squirted some mix right into the carb, thinking at least if there were a fuel problem it would start for a few seconds. it still will not start. The engine has low hours, so what am i missing????

thanks,

 

[Windykid]

Re: 2001 Mercury 8.0 HP won't start

If you have spark and fuel, you need to check for compression. Did anything happed to it while it was running?

 

[bikepro]

Re: 2001 Mercury 8.0 HP won't start

Windykid is right- Air, fuel, spark, and proper timing are the essentials. If you have good compression, good spark, and haven't messed with the timing, I'd say it's probably really flooded. Pull the plug/plugs, and pull it over a bunch of times off choke and at full throttle. Put the plug/plugs back in and try starting it again off choke at full throttle. If you still get nothing choke it at full throttle. It should pop off, given it has decent compression. Good luck

 

[eggy123]

Re: 2001 Mercury 8.0 HP won't start

I did not check for compression since it was running fine before this happened. Nothing happened while i was running it.

 

[eggy123]

Re: 2001 Mercury 8.0 HP won't start

Thanks for the input. I did what you said, still won't start. The consensus seems to be that I need to check the compression before continuing. I will give it a try.

 

[PassePartout]

Re: 2001 Mercury 8.0 HP won't start

I have had almost the same problem with almost the same engine.

I have a 2002 8HP. It has been running well (but maybe rougher than normal) all spring and early summer, but just recently stopped running while idling and would not start again (of course when i had 4 guys and a few cases of beer to take out to the mooring.)

I brought it home and know the following:
1) it has 1/2 gas from this spring and some from last year with a stabalizer.
2) The compression is 80 psi in each cyl.
3) There is good spark from both plugs.
4) the plugs are a couple of years old (maybe older), but i gapped and cleaned them.
5) the motor runs mostly at low speeds (it's on a harbor skiff) and i dont get to run it hot very much (do you still have to do this to modern outboards?)
6) the carb gets fuel; i took it off to clean it, but it was very clean anyway; (did not dissasemble fuel pump nor the primer pump)
7) i can hear the primer squirt fuel in to the chamber when i press it, imho it works as it should;
8) when i do get it started, there's lots of smoke
9) it will not start from cold after pulling the primer out 3 times as per instructions and previous experience (it almost always started first or second pull; then just stopped starting)
10) i can now only get it started by opening up the throttle to 10-50% and pulling the cord. when this happens, see #8;
11) when i do get it started, it will run rough for a bit, but then settle down and i can keep it at idle for at least 10 min.

I am going to put new plugs in first thing tomorrow morning and see what happens.

If that doesn't work, i'd like to know what might be wrong and how to fix it. I don't have much confidence in the local Merc dealer doing the repair, as the last time, they didn't do it right.

The boat and motor is used only about 10-15 hours a year, if that, and has been a great deal of trouble since purchase in 2002. The only thing that mostly worked well was that it started, ran, and didn't die. Now even that's not true.

Ideas?

tnx,
pp

 

[PassePartout]

Re: 2001 Mercury 8.0 HP won't start

As a followup, i think i solved the problem with the cheapest fix first: New Plugs.

Lesson Learned: new plugs every spring.

It starts now first pull, no priming.

tnx,
pp

 

[JB]

Re: 2001 Mercury 8.0 HP won't start

Passepartout, please don't hijack eggy's thread.

Eggy, I think you may have a sheared flywheel key, throwing the timing out.

Go to the Engine FAQs and check out the troubleshooting in "Outboard won't start".