Before I start my outboard that’s been sitting?

[Douglasdzaster]

Hello everyone, I have a question about my 1992 40 hp Yamaha which has three carburetors.
I completely rebuilt all three carburetors 2 years ago. Installed a complete new fuel system with FW separator and all as the motor had not one filter on it when I got it. Replacing everything but the carburetors bodies. Ran only non ethanol premixed fuel with an additive (probably overkill) Star Tron HD marine and synthetic 2 cycle oil. After enjoying it several trips I found several things that needed attention.
I had to do some work on the boat itself which turned into almost a complete rebuild. Long story short I haven’t started the motor but once in a year 6 months ago. Reason is I have to premix the fuel and I don’t like keeping premix stored long periods of time. Even though with the additive the gas may be good the oil might not. Also the plastic tank vents routinely. And if it’s not kept full there’s condensation. Etc. etc.
I should have mixed a little occasionally to start the motor but didn’t.
Alllllll That being said.
I’m ready to run it and wanted y’all’s opinion. I had pulled the drain on each carburetor after running it last time but didn’t run it dry first and pulling those plugs doesn’t drain 100% of the fuel.
The clear filter on the side of the motor still had clean , fresh smelling fuel in it when I just pulled it. Should I take a chance and mix fresh fuel and run it? Or should I change the fw separator( which has just a few hours on it),flush the lines , pump fresh fuel in the carburetors, drain then prime and start?
I’m trying not to have to pull and clean the carburetors and maybe kits. Which are three times the price they where 2 years ago. And I just spent a lot doing all the work I did (trying to ease the heat from my lovely wife, it’s time to stop for a while and use it before continuing) Lol.
I’m hoping I don’t have any corrosion in the carburetors or stuck floats. I can’t remove the bowls without pulling the entire assembly. From the outside they look good but that’s not seeing much when a carburetor is concerned.
Another option is to go ahead and pull the carburetors and clean everything if there’s a chance that running it may cause damage. I’m trying to avoid it but if it’s best it’s worth spending the time rather money later.
My cover also goes over the motor and the boat has been covered every evening when I stopped working on it. Never got rain in it the whole time.
I’m going to go ahead and change the lower unit oil since it’s been in it a year. And had just installed an all new water pump before all this was started. Again hopefully the impeller didn’t dry rot or something. I NEVER dry start the motor like I see some do. I worry about the seconds it takes the water to start coming out of the p hole. Lol
Basically I had done a ton of neglected maintenance on the motor when I got it. New thermostat , corroded bolts etc. I can pull the cowling off now and it looks new. What I couldn’t get to by hand I cleaned with q tips etc. then protected the whole top end by spraying with fluid film. I haven’t had any dirt or things that I can see get past the cowling and sticking to the Fluid film. Every few months I would clean it all off and re apply. At first I had tore torque some things because after a while with the film on it they loosened up a little. But only once l also check everything’s torque frequently when I was running it regularly.
I appreciate any opinions and advice on how I should proceed. That’s my history on it.
If there’s any tips about anything else I should do before starting I would love to hear them. Like I said I’m just trying to address anything that I can prevent from needing to repair because I started it without checking something.
I wrote another novel. I apologize but I get carried away on here sometimes or worry about not providing enough information.
Thanks everyone. If it wasn’t for the site here there are a lot of work on the boat I couldn’t have done. Everyone on here is awesome for helping me out the past couple years.

 

[Pappy]

Drain carbs and lines including your line from the tank to the engine. Fresh fuel and oil, purge the system, start it and let it idle. Idle system runs on the smallest passages and jets. If it idles normally chances are it will be okay up through the range. Common sense prevails though! Pay attention as you get up on plane all the way through the range.

 

[St.Clair Flatsrat]

Do not forget to pull plugs lubricator cylinders and rotate flywheel on motor by hand. Then reinsert plugs and tighten to specs

 

[Douglasdzaster]

Drain carbs and lines including your line from the tank to the engine. Fresh fuel and oil, purge the system, start it and let it idle. Idle system runs on the smallest passages and jets. If it idles normally chances are it will be okay up through the range. Common sense prevails though! Pay attention as you get up on plane all the way through the range.

Thanks for the input. Yea I’d rather go through purging everything including changing the fuel water separator than start it and bam carburetor trouble.
I’ll definitely be paying attention to how it runs through the range up to wot. I don’t want to run it with the fuel not properly flowing.

 

[Douglasdzaster]

Do not forget to pull plugs lubricator cylinders and rotate flywheel on motor by hand. Then reinsert plugs and tighten to specs

I thought about that as well. I should have at least rotated the flywheel every now and then so gravity wouldn’t settle everything off the walls.
I’ve done a lot of small engines that sat up before starting and had success as far as cleaning or replacing fuel line cleaning out the tank then I’d spray some wd40 in those cylinders and let it sit while I did the other stuff. Today if there’s ethanol involved there’s no getting around pulling the carburetors. I have to go pick up another mower from a lady that told me it’s been sitting since I put the new battery in last year. Lol It has little black specks of fuel line coming out when I pulled a sample from it. Ethanol is eating up everything. I’m lucky and have access to non ethanol which I still treat because you never know what got dump in the stores tank.
Is there anything special I should use to lubricant my outboard cylinder? Any one product better than the rest? I’d hate to scare the cylinders. This has been my first outboard to seriously dig into. I’ve learned a lot but at the same time I’m glad I had experience in small engines. Like I said I had it running great after I went through it. Then I let it sit. And I knew better than to let anything just sit. Sad thing is all the hours I spent on the boat this past year I was right there. I’m hoping the Star Tron helps with any fuel that was left in the carburetors. That stuff is new to me as well. I was just trying it out. I don’t believe in a mechanic in a bottle but do know how a couple of other brands will help with ethanol in fuel that’s been sitting.
Thanks so much for the reassurance I was headed in the right direction.

 

[LaqueRatt]

Call me nuts if you want, but this is my process when I get any sort of old engine/motor. Fill it with fresh gas, hit the key/pull the rope. They almost always start up. Maybe I'm just lucky. Got another 'rude that has been sitting a few weeks ago. With the weather getting warmer I'm looking forward to putting it in the barrel and giving her a pull! Betcha it starts.

 

[Tin Man]

Having rebuilt the 3 carbs on my Honda 50 (7 mo old gas) due to clogged idle jets, I am very careful about using fresh fuel. As already mentioned.....use fresh gas and remove any old gas in fuel system (hose, tank, filters, etc). I used Honda Stabil on my Honda, but am now considering the new Techron Marine for fuel stabilizer on my new Mercury. I also use Yamaha Ring Free (of which the Techron is supposed to be very similiar) which is a very good product for carbon deposits. The stabilizer and Ring Free are two different products.

But again, FRESH fuel and a fuel stabilizer are a MUST IMO. If you have rebuilt carbs (which you have), then you know why I am adamant about this!

 

[Douglasdzaster]

Call me nuts if you want, but this is my process when I get any sort of old engine/motor. Fill it with fresh gas, hit the key/pull the rope. They almost always start up. Maybe I'm just lucky. Got another 'rude that has been sitting a few weeks ago. With the weather getting warmer I'm looking forward to putting it in the barrel and giving her a pull! Betcha it starts.

You should go to Vegas. When I first got this one it had been sitting outside for at least a year or two. I replaced the rotten fuel line added a filter and it fired right up too. Took it for a test run it it skipped across the water. 2nd trip I took the wife fishing and it ran awful and was flooding fuel. We spent the day on the trolling motor.
I got home and knew the floats were sticking. Figured I’d pull the carburetors clean them up and throw them back on said my Small engine guy self(first outboard). Those carburetors were so corroded and I still don’t know how it ran at all. I started looking for replacements they looked so bad. Unfortunately it’s hard to find some parts for a 1992 Yamaha 40 MSHQ. I soaked those carbs and had to be very patient trying to remove the jets etc. I cleaned the seats with tooth paste and cotton on a wooden skewer. Polished the up like new. Did the jets too. Unfortunately everything was so bad that when I did this two of the seats where oversized and the needle not sealing. Same with the jets. I ended up replacing everything except the carburetor bodies which I never thought I’d get right.
The main jet in the middle carb had to get the next size up because the original was no longer made.
Then I had to learn how to resync three carburetors and spent a lot of time at the dock making adjustments. It would seem like I had it and an hour later I’m back at the dock.
It was hanging in there finally until this. I need to be actively hunting for carb bodies. Maybe one at the time. Lol

 

[Douglasdzaster]

Having rebuilt the 3 carbs on my Honda 50 (7 mo old gas) due to clogged idle jets, I am very careful about using fresh fuel. As already mentioned.....use fresh gas and remove any old gas in fuel system (hose, tank, filters, etc). I used Honda Stabil on my Honda, but am now considering the new Techron Marine for fuel stabilizer on my new Mercury. I also use Yamaha Ring Free (of which the Techron is supposed to be very similiar) which is a very good product for carbon deposits. The stabilizer and Ring Free are two different products.

But again, FRESH fuel and a fuel stabilizer are a MUST IMO. If you have rebuilt carbs (which you have), then you know why I am adamant about this!

Just yesterday I read a big marketing write up about the new Techron marine. It explains how they did their testing etc.
Other brands use petroleum products to do the cleaning while Techron uses detergents that’s supposed to be pretty strong. When I did my rebuild I replaced everything but the carb bodies and they should have been replaced but I already had to hunt most of the jets etc from different places. 1992 Yamaha 40mshq three carburetors. When I did run across carburetors that might work on eBay or where ever they were have as much as I paid for the boat. I worry that detergents like that may eat at those old bodies some how with my luck. I should’ve been looking for replacements all this time. I like to have never got them dialed in to where it would stay. It was doing good though until I parked it. I’m hoping the fact that I ran strictly non ethanol fuel and always an additive to the mix that I can get away with starting it with a clean fuel system and not have to pull those carburetors again.

 

[GYPSY400]

I think you'll be ok as it seems you took the proper steps when you put it away last time out. Like Pappy said, the smallest ports are the idle circuit, so that will be the first place trouble shows.
If possible, run it in a barrel rather than using muffs. Muffs will tell you a motor runs, a barrel will tell you if it runs well.

 

[LaqueRatt]

For the record, I don't take these motors out onto the water without going through them. I just get a kick out of seeing if they'll run without any tinkering.

 

[Douglasdzaster]

For the record, I don't take these motors out onto the water without going through them. I just get a kick out of seeing if they'll run without any tinkering.

Before every trip I check everything and start it before I leave the house or the night before. I frequently check torque on head bolts,thermostat , lower unit etc. Gives me piece of mind with a 31 year old motor.
Then I go and let it sit without starting. If it doesn’t run right I’m really going to be kicking myself.

 

[Fishingman48]

I hear yah on not running right last merc. I had would start right up I get ready to go out and after getting warmed up it would like skip kick periodically. never used it went. sold it as is new owner stated no prob. would find out prob. I guess he did as never heard back from him
and i went out on my pelican pond jumper with my 6hp/ now i am set up with a 14 ft aluminum w/ a 20 hp merc ready to go! engine purring.

 

[Douglasdzaster]

I hear yah on not running right last merc. I had would start right up I get ready to go out and after getting warmed up it would like skip kick periodically. never used it went. sold it as is new owner stated no prob. would find out prob. I guess he did as never heard back from him
and i went out on my pelican pond jumper with my 6hp/ now i am set up with a 14 ft aluminum w/ a 20 hp merc ready to go! engine purring.

This Yamaha was doing some funny running after warm up and I found the tube for the water pick up above the pump not connected properly. Once it started getting the right amount of water all was WOT all the way.
It’s a 1992 40 hp. Pull start and cold starting would about wear me out until I finally got everything dialed in with the link and sync and adjusting all three carburetors several times. This was after I completely rebuilt all three.
1/8 of a turn off and it’s not happy.
If I do end up pulling them again I’m counting every turn and taking measurements with a caliper. Shouldn’t need kits. Cleaning at the worst.
Good thing too. When I rebuilt them all three kits OEM where around $80. 2 years later and they’re $250.
Mines pushing a 1983 16/52. Been on land for a year while I had to do some serious maintenance /rebuilding to the boat.
It made the boat skip pretty good before. Now I’ve removed a lot of weight replacing the old flooring etc. Can’t weight to see how it does now.
Pretty weather for three or four days starting tomorrow and I hope to be finished and going fishing.

 

[thill]

So... What happened?

My guess is you drained the fuel and the engine ran flawlessly. But let us know.