20hp mercury tiller, won't start

[AF rigger]

Hello every one. Just bought my first fishing boat, and it ran fine the first time out to check it out. Took only 2-3 pulls to get it started. Since then I can not get it to start. I have replaced the plugs and made sure the fuel and oil was right. Everything looks clean as a whistle. Thinking it might be the fuel filter, but can't figure out how to get it off! Any help would be greatly appreciated, as I hear a catfish calling my name at the lake. The serial number (if it helps any) is G170596

 

[Dave588]

Re: 20hp mercury tiller, won't start

The fuel filter is probably mounted by a rubber unit so you have to hold the top carefully and twist bowl off?

My 20hp tiller merc won't start either. I had it in storage for last 8-9 years. I replaced the water pump impeller, sparkplugs and rebuilt carb. I pulled it without plugs first because I put oil in cylinders before storage. I pulled it assembled and I get a gas smell from exhaust, no spark. I am gonna research testing the kill circuit, stator output and probably make a dav accessory for my multimeter.

 

[Mi duckdown]

Re: 20hp mercury tiller, won't start

Dave start your own thread.
I know you are trying to help BUT.
it just make mass confusion diagnosing different problems at the same time

 

[Mi duckdown]

Re: 20hp mercury tiller, won't start

rigger.(if it helps any) is ?170596
missing a number ?

 

[AF rigger]

Re: 20hp mercury tiller, won't start

It appears to be missing a letter in the beginning. From what I figured out, it may be a "G" in front and is a '95 model, pull start long shaft.
maybe that helps

 

[Dave588]

Re: 20hp mercury tiller, won't start

Not trying to diagnose different problems at the same time. Same motor, same problem.
I told him that I verified I had gas first, spark second and so on.

Dave start your own thread.
I know you are trying to help BUT.
it just make mass confusion diagnosing different problems at the same time

 

[AF rigger]

Re: 20hp mercury tiller, won't start

quick update here. WE have spark, we smell gas in the cylinders after we pull the rope. The run/stop switch is functioning properly. going to check the carb next to see if it is junked up somehow.

Any other suggestions on what to check next??

thanks for looking

 

[Dave588]

Re: 20hp mercury tiller, won't start

I bought a carb rebuild kit. It was $40 from NAPA. I think it's about same price at USAMarine. That allowed me to disassemble the carb and shoot carb cleaner thru every jet and port. After a week of holding fuel, I went back and re-tighten everything on carb. When you run outboard after that, you'll probably have to adjust idle screw.
I was troubleshooting spark but everything works. Mine started right up, idles fines, runs in gear.

 

[AF rigger]

Re: 20hp mercury tiller, won't start

Thanks Dave. took the carb off yesterday and everything looked okay. If I can't get it to run after I replace the fuel in the tank, then I will try rebuilding it. Thanks for the update.

 

[Mi duckdown]

Re: 20hp mercury tiller, won't start

Rigger. not a big fan of removing carb and not rebuilding/re gasket carb.
if i'm going to remove carb, i do a rebuild . Just my .02
Some orifices on the carb can not be accessed buy air. I also run heavy mono line thru all orifices(SP?) when disassembled, to make sure there are no blockages.
It only takes 1 small piece of crap to make it run like crap.
Again my .02

 

[Jake_MN]

Re: 20hp mercury tiller, won't start

Pull the plugs, dry the electrodes completely and reinsert. Pull the handle a few times. Then remove the plugs again. If the plugs come out with wet electrodes, you're getting fuel to the cylinder. If they come out dry you have a clogged carburetor. As the others have said even the slightest little piece of gunk can dislodge and clog up the jet.

 

[Dave588]

Re: 20hp mercury tiller, won't start

I'm running Champion L76V plugs in mine. No gapping. You may be able to disassemble carb several times to clean everywhere, but when it runs, you'll want to new set of gaskets before you use it. I removed my idle screw to clean. When I reassembled I turned it all way in, backed out 2 turns and re-adjusted when running. You could turn it all the way in, counting turns as you go to be more accurate.

 

[AF rigger]

Re: 20hp mercury tiller, won't start

Thank you for all the great advice fellas! Cleaned the carb, cleaned the filter, put fresh gas mix in and she fired up on the second pull! what a great feeling to have it run again!

 

[Jake_MN]

Re: 20hp mercury tiller, won't start

Very cool, glad it worked out for you.

 

[Dave588]

Re: 20hp mercury tiller, won't start

Ditto, I had a big smile when mine caught and ran. I think that's ethanol gas for you.

 

[AF rigger]

Re: 20hp mercury tiller, won't start

went out to the lake this afternoon and ran her good for about three hours! started right up on the first pull every time too. runs like a scolded dog, I estimate around 25-30 mph. ran a complete 8 1/2 mile loop with out it missing a beat. now if I can just get all the paperwork straight and the depth finder I will be happy as a lark. )

Thanks to all who helped!
salutes to all!

 

[3rd Generation Lund]

Re: 20hp mercury tiller, won't start

quick update here. WE have spark, we smell gas in the cylinders after we pull the rope. The run/stop switch is functioning properly. going to check the carb next to see if it is junked up somehow.

Any other suggestions on what to check next??

thanks for looking

Rigger - How did you check the run/stop switch. Same engine, same issue, need to check run/stop now. Thanks!

 

[aussieflash]

Re: 20hp mercury tiller, won't start

This thread is over 9 months old,if you need help start your own thread....its the only way.Good Luck.