mercury outboard wont start

[liquidice]

The rag over air intake is a great idea. I push the meaty part of my palm on the carb throat for the same effect. As mentioned, it creates a seal, forcing gas through the fuel jets when you pull the starter cord. Pull slowly with the throttle low, and the motor is not like to start.

This certainly sounds like a fuel delivery issue. Cleaning the carb is usually the ticket, but sometimes if you can just get it to fire, and run it for a while with freshly mixed gas, the additives in the gas can break down the varnish deposits. Good luck.

[MVNightWatch]

I second the person who said check that kill switch if it’s the “man overboard” split fork type. Wiggle it, spray it with electrical contact cleaner, and wiggle it lots more. They are notorious!

[le chat beaute]

Many times after a outboard has sat for awhile, the float will stick. Tap bowl with a screwdriver handle and usually comes free. Always run gas out of outboard before storing as it goes bad.

[thomm225]

Originally Posted by winschwab

I have a 2015 3.5 and a 2016 6.0 Tohatsu. I run non-ethanol with Stabil and still have lots of trouble. Often hard to start, but not consistently. Often acting starved for fuel: will only run with choke half way out. I have disassembled and reassembled the carb re manual instructions, but I'm not sure I'm really getting at the problem. Any more suggestions?

Sounds like the carburetor is still dirty. Try running ethanol fuel …..and treat with stabil if you keep the gas over the Winter

[Buzzman]

Can't believe no-one suggested checking the plug gap.....and grounding against block while turning over to check for spark.

Air. Fuel. Spark.

Not rocket science.

[thomm225]

Originally Posted by Buzzman

Can't believe no-one suggested checking the plug gap.....and grounding against block while turning over to check for spark.

Air. Fuel. Spark.

Not rocket science.

Right.

it's not rocket science if you understand engines but the OP is all about fouled plugs and starter fluid even though plugs don't usually get fouled on a four stroke.

Plug gap was mentioned on post#8.

[thomm225]

Originally Posted by winschwab

I have a 2015 3.5 and a 2016 6.0 Tohatsu. I run non-ethanol with Stabil and still have lots of trouble. Often hard to start, but not consistently. Often acting starved for fuel: will only run with choke half way out. I have disassembled and reassembled the carb re manual instructions, but I'm not sure I'm really getting at the problem. Any more suggestions?

Clean the carburetor like this video and that should fix your problem.

https://www.youtube.com/watch?v=oQELbAUZ53g&t=233s

[Buzzman]

Ahh, I missed the post #8 ref to plug gap.

I am not at all mechanically minded, having three left thumbs, and almost invariably break anything I touch. Even picking up a spanner is often enough to break whatever I'm contemplating "repairing".

But I can usually manage to get my ancient Seagull motor to start. Fresh fuel, clean / gapped plug, choke the carb, and it almost invariably goes first or second pull.

I once had a set to like the OP when it wouldn't start one morning after having run faultlessly the day before - till I recalled the need to 'choke' the carb by hand on cold mornings. Went first pull after I tried that. Felt a right git, too. Proper 'Doh!' moment.

It's easy to get fixated, and sometimes stepping back and re-thinking can point to a previously less obvious solution. Helpfully, British Seagull's Owners Manual advises that if the motor hasn't started within f pulls, YOU have clearly done something wrong. So, don't balame themotor, go back over the process and start from the beginning. Air. Fuel. Spark.

Having said that, I concur with the consensus that carb cleaner would likely be of assistance in the case of the OPs Mercury. It only takes a wisp of a coating on the jet or needle to cause problems.

[Tellie]

Originally Posted by thomm225

Clean the carburetor like this video and that should fix your problem.

I have to do this about as often as I fill up with gas on my 6hp Merc. Yet I have a 26 year old 6hp lawn mower with a Briggs and Straton that stills starts on the first or second pull and I've only changed the oil on it twice. Wonder if It's time to change the air filter?

[Jimmyhenry]

One squirt of ether /starter stuff and a hard pull on full throttle not choke. If it doesn’t start it has to be electrical.

Remove the spark from the engine. Reconnect and get some else to hold the plug against the engine. Give it a good tug. If no spark get it to a marine shop.

Pete

[bimini blue]

so in the end, the float valve was bad, replaced the carburetor, fuel filter and fuel pump
started right up

think the real key was the fuel filter, I had used gas station gas and not started the engine in months
I now carry extra fuel filters and will not use gas with ethanol

the good news if any is that I was able to do the repair myself

[liquidice]

Originally Posted by bimini blue

so in the end, the float valve was bad, replaced the carburetor, fuel filter and fuel pump

started right up



think the real key was the fuel filter, I had used gas station gas and not started the engine in months

I now carry extra fuel filters and will not use gas with ethanol



the good news if any is that I was able to do the repair myself

Awesome news! Thanks for posting the results.

[belizesailor]

Its unlikely there is actually anything wrong with the carb. Clean it properly and keep as a spare.

[thomm225]

Originally Posted by bimini blue

so in the end, the float valve was bad, replaced the carburetor, fuel filter and fuel pump
started right up

think the real key was the fuel filter, I had used gas station gas and not started the engine in months
I now carry extra fuel filters and will not use gas with ethanol

the good news if any is that I was able to do the repair myself

Glad you got it fixed!

And BTW, replacing the fuel filter is part of the yearly PM's.

And remember, it's fine to use gas station fuel …… with 10% ethanol, but if you plan to not use it for months mix in some stabilizer. I'll use the rest of this years gas in the Spring

Some folks mix in stabilizer if they think the fuel will be around for just one month to avoid potential problems

Btw, these engine were built to run on 10% ethanol

[NYSail]

Starting simple..... make sure the correct kill switch key is in place. It’s happened a couple times on my engine that the key will come out and the wrong one (thinner) gets put on.....( I still have the key ring with three on it from factory). It’s a duh moment.

Greg