'89 Merc 35 HP stalled,won't start

[ottawan]

We were out on a beautiful day. Motor ran very well all day. Usually very easy to start-hot or cold.

This time, we stop along our trip to try some fishing. After stopping for a few minutes, motor turns over fine but won't start. Remove the plugs, seems to be very good spark on both cylinders. Give it a few cranks without the plugs to clear out any excess fuel in the cylinders.

Still won't start. Give the ball a few squeezes, it gets hard, still no start.. Gas tank is still half full, vent is open. Luckilly we weren't too far from our starting point. Got towed to our dock.

I don't have a manual for this motor. Any ideas on any quick checks I could do next time I head out there?....keeping in mind, this is pontoon and I'll be working over open water. Hate the thought of losing any small parts and having to dive to get them back.

I'm hoping to get a few more weekend rides in before pulling it for the season.

 

[corm]

Re: '89 Merc 35 HP stalled,won't start

Hi,

Check your tank for water.
If you have water in the tank you could now have water in the carb.

 

[ottawan]

Re: '89 Merc 35 HP stalled,won't start

Went back to check it over the weekend.

Disconnected the fuel line after the filter (before the carb). Turned it over, lots of flow and pressure so that means pump works and filter is not plugged. Opened the top plate on the carb bowl- bowl was full of fuel.
Installed brand new plugs. Appears to have lots of spark- jumps at least 1/2 inch when held close to the engine block.

Used a squeeze bottle to add mixed gas directly into the cylinders. Cranked it over and nothing at all. Tried squirting fuel directly into the carb and still nothing. Plugs were wet (gas).

Checked all levers and linkages from the forward/reverse shifter. All solid; no sloppiness, bent linkages or loose connections.

There seems to be spark, we added fuel directly into the cylinders and still nothing.

The only thing I can think of now is that somehow the timming changed.

Has anyone ever run into a situation where the timming somehow shifted?

 

[Tootsie]

Re: '89 Merc 35 HP stalled,won't start

HI, I don't have a big outboard like you have.. Mine is only a older 7.5 Merc. But I seem to have the same problems you have. Moter died and just would not turn over. Lots of spark.. (new plugs )So I took it in. They changed the fuel pump and bowl said the plugs and all were just fine. I bought a new gasline hose and ball for it and changed it. It ran awesome for part of a day..next day I take it out to go fishin..it started just fine...and died.. and will not start since. I also had made sure the tank was drained and used fresh gas. What happened. !!! Wonder if its in the tank itself?? Lots of gas going through though I heard that sometimes in older tanks the pump mech disingrates and may plug the gas linehose ?? Help... I have fishing to do...

thanks


Lady Fisherman.

 

[corm]

Re: '89 Merc 35 HP stalled,won't start

Has anyone ever run into a situation where the timming somehow shifted?

Hi,

Tootsie, Please start a new thread with your problem.

ottawan,
You did not happen to take the sparkplug wires out of the coils and get them back in the wrong ones by chance.
I have not seen the timing change on that engine. it is possible that the ignition system is going bad. You will need a DVA meter to check most of the ing sys. If you have a timing light you could check the spark and make sure it is firing when it should be and that it is firing 180 degrees apart. I would take the plugs out when spinning the engine so the starter does not have to work so hard when checking the spark & timing.
Use some white chalk to make a mark 180 degrees from the Merc timing marks on the flywheel it just needs to be close so do not worry about doing it perfect. I would use the TDC mark to measure off from as it will be easy to use. You can advance the throttle to get TDC to align with the pointer Then move the timing light to the other plug wire and see if it fires on the 180 deg mark. This will at least let you know if the engine is firing when it should be.
I looked like you covered the rest of it fairly well.

Please be careful that you do not ground the plugs by the sparkplug hole. If fuel is coming out of them while turning the engine over you could get a little explosion that will scare the girls. I usually unplug the gas line so it is not pumping fuel so much. I also spin the engine a few seconds to help clear fuel in the cylinders before preforming the test.

Here is a link to some VOM and DVA ing tests.
http://www.maxrules.com/cdi/MercDva2003A.pdf