Wife ain't happy - outboard has turned flaky

[ontherocks83]

second what A64 said. Buy a complete rebuild gasket kit for the old carb, have a mechanic rebuild it and keep it as a spare. This way if you are out in the middle of nowhere and have a problem you can just swap it out and be up and running in minutes.

[Kenpimentel]

Definitely the plan. After using the motor a bit, it is running marginally better, but still dies on idle - unless I pull the choke out.

Difficult to try to fix it while we still need to use it so much. I hesitate to completely disassemble in case I do something stupid and can't get it to run. So, I might now wait for the new carb and the compression testing gear. Should have an update in a week.

[a64pilot]

Since your running it, try some sea foam, pretty rich mixture, say one can per 5 gls., it may well make things better.
If it were you main jet that was clogged, running it would result in a very lean mixture which could harm the engine, but since it appears to be in the idle circuit, I don't think any harm will be done.

[Therapy]

Originally Posted by a64pilot

Your idle circuit is clogged, I missed the point before where you said it ran OK at high throttle settings, of course that is when it's off the idle circuit and on the main.

Not to sound ridiculous, but what are you soaking it in? A one Gl can of carb cleaner with a strainer basket, right? You are completely dis-assembling the carb, removing all plastic, O rings and gaskets before soaking?

I'd bet lunch it's the idle circuit, and I don't do that unless I'm real sure

I agree.
The idle circuit holes/passages are so small (and convoluted)in these engines that the tiniest bit off "stuff" (whether it be a bit of hose rubber or gunk build up) will stop it from idling correctly.
If you can correct it and make it "better" with a speed screw adjustment you may have not corrected the problem. If you inadvertently lean out the fast circuit you can easily burn valves. Then you are pretty much done. This is not a high chance but possible.

[Therapy]

Originally Posted by jcapo

All jets and nozzles should be removed when cleaning carb.

These days most of the jets are covered with metal plugs not meant to be removed. (Maybe special tools.) Hard to do in the garage of most without collateral damage.

[Therapy]

Originally Posted by a64pilot

Your best bet is the carb you have ordered, once that fixes it, have the old one professionally cleaned, that way you'll never need it.
If your using real carb cleaner, then the plastic and O rings that may have been left in the carb you may have to replace.

Did you use something like this?
NAPA AUTO PARTS

There is always that.

[jcapo]

Originally Posted by Therapy

These days most of the jets are covered with metal plugs not meant to be removed. (Maybe special tools.) Hard to do in the garage of most without collateral damage.

I didn't know that was the case with 4 stroke carbs. Another good reason to stick with a 2 stroke.

[Therapy]

Originally Posted by jcapo

I didn't know that was the case with 4 stroke carbs. Another good reason to stick with a 2 stroke.

Yea. fewer "user serviceable" parts these days. My Merc. 6 hp 4-stroke had the idle problem too. I did not want to chance punching/pulling the plugs so I just used seafoam injected into what I could reach with a syringe. Then I ran it and injected into the carb till stall. Let sit. Repeat. After a few times I got it to idle OK again.

Honestly I don't know specifics on the 15 but would bet it is pretty much made the same way.

Before we sold the cat we were planning to, one day, get to the Bahamas where I planned to pick up a 2-stroke. For all these reasons and more. My last Yamaha 9.9 was stolen and then you can't buy them any more.

[bizzy]

keep the outboard , she will eventually leave

[JPA Cate]

Originally Posted by bizzy

keep the outboard , she will eventually leave

So, you think a little mysogynism is good for business bizzy?

Had it not occurred to you that the problems with this motor might not be a bother to both the OP and wife?

The implied disrespect to his wife stinks big time. Besides, he's asked for help, not smarting off.

End rant.

Thanks to the rest of you guys for helping the OP learn about this.

Ann

[4arch]

The recommendations to jump through whatever hoops it takes to get a 2 stroke in these outboard threads always amuse me. Whenever the subject of the holding tank discharge rules comes up on this board there's always a vocal majority who become incensed that anyone would even so much as think about pumping out inside the 3 mile limit. Yet some of those same people seem to have no compunctions about running an outboard that spews oil and unburned fuel. I don't want the water despoiled in either way, but if I had to choose I think I'd rather have the human waste in the water over oil. Not an environmental extremist by any means but the downsides of a 4 stroke (increased weight, increased complexity, decreased low end torque) are worth it to me for the clean wake plus the increased fuel efficiency and quieter operation.

[a64pilot]

Been said a few times here, but the four strokes are changing, My Suzuki is 20 HP at 99 lbs, and will get four "American" adults (that's about 800 lbs) plus a few supplies on plane with my 3.10 RIB, total weight 1100 to 1200 lbs. Two stroke 15 HP Yamaha won't.
Much as I love them as I have many years porting and polishing 2 stroke cylinders, the day of the two stroke except maybe in very specialized uses is about gone.

Almost all little engine carbs built in at least the last 20 yrs for US consumption have a plug over the idle jet adjustment screw, almost always drilling a small hole in this cap, threading in a small sheet metal screw to pull it out works. Look up Dynojet instructions on how to install a Dynojet jet kit in a motorcycle for complete instructions.
Main circuit is almost never adjustable, you have to change jet sizes to make a change, except of course any trash will make it go lean, and lean is hot, and hot is bad.
Myself I adjust the idle circuit to as lean as the engine will run smoothly when cold,(two strokes) and the high speed circuit to as rich as it will run smoothly. Lean on the bottom end as that helps prevent "loading up" and smoking at idle, and rich when wide open as rich is cool temp wise and makes the most power. It's the way we used to set up Motorcross and Road racing bikes back in the day when two strokes ruled.
For those that may still partake, how many two stroke dirt bikes are left?

[a64pilot]

99% of poor running issues with these little four strokes is carburation, the engines are very well made, rarely is it something like a cylinder head gasket, and usually electronic ignition either works or it doesn't.

Ethanol fuel is often the cause, and ethanol is very simple to test for. Take a graduated cylinder, a canning jar is perfect, put a small amount of water in it, like 100 cc's fill the rest with gasoline put the lid on it and shake it several times and let it sit. If there is Ethanol in the fuel, the level of water will increase as Ethanol combines with water, if the level remains unchanged, there is no Ethanol in the fuel. Ethanol is actually pretty expensive, with gas prices they way the are now, ethanol is often not being put in the gas, except in some states laws were passed requiring ethanol to be used. Long winded but this shows how to test

https://www.youtube.com/watch?v=RbDAw4a6Ck0

[Kenpimentel]

Thanks again for all the advice. Couldn't do anything today, maybe tomorrow test some of these ideas.

I've never heard of Sea Foam, I'll try to get hold of some.

BTW, I did an interesting test comparing a 15hp Yamaha 2-stroke versus my 15hp 4-stroke Mercury while in the Bahamas. The results were completely surprising (to me). The 2-stroke weights about 90lbs while my 4-stroke weighs about 115lbs. I could not get my dinghy to plane - even with just me on it! This compares to our 4-stroke getting all 3 of us to plane.

The best reasoning we could come up with is that our dinghy is a Caribe 9.5 - which is a deep V design. It needs a lot of torque to get it up out of the water. Take a look at the torque curves on a 2-stroke vs a 4-stroke. You might be amazed at just how different they are.

One other difference in our experiment - our 4 stroke had the "wings" on it while the 2 stroke didn't. So the comparison wasn't perfect. I did remove the wings from our 4-stroke as a test - and it definitely made a difference - but I don't think all the difference. The torque curves are substantially different, and is a radical difference between the two engines for us and our dinghy.

I think if you have a flatter bottom dinghy, the 2-stroke will work better as it can get you onto a plane and then it can rev up to where it's torque is.

Someone suggested a deeper pitched prop, but I'm not sure it is easy to come by in the 9" size?

Anyway, I decided to keep my 4-stroke after that experiment. I'm sure others will have a different experience with their dinghies.

[Old Snipe]

4 Strokes get a bad rap among some of the old school boaters. I have many friends that were the same way until they actually owned a 4 stroke.

The carbs in any 2 stroke will foul just as fast as any 4 stroke if the owner doesn't pay attention to the fuel. There are conditioners out there for ethanol gas that can protect your fuel for up to about 4-5 months. Some say longer.....but I wouldn't trust it.

I see a lot of boaters blaming particular engines and fuel, when they really should take a closer look at their own practices.