2-stroke 25HP mercury stalls while accelerating.

[Jay415]

which is the high jet? the air/mixture screw? that's really the only adjustment beside the idle screw.

I've looked into non-ethanol fuel and the closest place I found is over 1 1/2 hours away. The gas I'm running still has seafoam in it from my first trial. it's a little diluted now though. it's definitely not lower unit oil that I see.

 

[Buddychrist]

Drop both the air mix and the idle down a tad and see if it helps. Keep the idle clean but just a little lower and keep the top end good but try the PWC oil from Walmart that's made by quicksilver it really helps.

I'm sure there's non ethanol closer, if you PM me your city I can hunt around, the first place I found was an hour away but after I did some phone calls I found the almond oil company.

 

[Buddychrist]

https://pure-gas.org/extensions/map.html

There's 91 octane near Syracuse NY
The Nice N Easy on Bartell Road in Brewerton, NY (just off of I81).

 

[Jay415]

Lol, That's a few hours away. I'm on long island in Nassau County.

I started using mercury 2 cycle synthetic. But I'll try the one you reccomend.

 

[Buddychrist]

The mercury two cycle is good stuff too! Are you running Premium?

You could try getting a small gallon of sthil premix non ethanol in 50:1 and run it through.

 

[Jay415]

No I've been using 87 octane

 

[Buddychrist]

No I've been using 87 octane

You should be running premium, empty out your current tank and run premium with the mercury 2 stroke oil. That should stop any misburning!

You'll get a much hotter and cleaner burn giving you better throttle response and less oil residue through the hub! Give it a shot and tell us how it goes if you get a chance this weekend

 

[crazymanme2]

I've always ran 87 octane in my 25hp Merc with no problem. :lol:

 

[Buddychrist]

I've always ran 87 octane in my 25hp Merc with no problem. :lol:

What works for one person might not work for another... The manual says 89 octane, I'm running 92 and it does show a difference especially in throttle response...

The reason I say he should run premium is high elevation on a newly built carb if he is having oil through hub he isn't getting a complete burn and a higher octane will help with that.

Look at your elevation on your GPS and tell me what you've got and I'll give you the correct jetting size per service manual

 

[crazymanme2]

You sure nobody messed with the timing or got out of whack?I used to race these motors & know them inside out.

The manual says 89 octane, I'm running 92 and it does show a difference especially in throttle response...

It also has to do with your timing. If I want all the speed I can get I will run 93, no ethanol & bump the timing as far as I can go.It will give me another 3-5 mph.I also run a little bigger jets.(never hurts to be a touch on the rich side)

Alot of outboards have oil through hub especially if you idol alot.I even get it on mine sometimes.I'm not saying higher octane won't give you a cleaner burn just he probably has other issues.

 

[Buddychrist]

You sure nobody messed with the timing or got out of whack?I used to race these motors & know them inside out.

The manual says 89 octane, I'm running 92 and it does show a difference especially in throttle response...

It also has to do with your timing. If I want all the speed I can get I will run 93, no ethanol & bump the timing as far as I can go.It will give me another 3-5 mph.I also run a little bigger jets.(never hurts to be a touch on the rich side)

Alot of outboards have oil through hub especially if you idol alot.I even get it on mine sometimes.I'm not saying higher octane won't give you a cleaner burn just he probably has other issues.

He Just did a carb rebuild and set the timing, and jets getting it back to factory settings. I know they all put oil through the hub at "idle" but it still shouldn't be globs of oil coming out and it got worse after his carb rebuild. Which goes to tell me turning down the jets an 1/8th turn and run higher octane will fix it.

I only run premium non ethanol in all my boats and smaller engines (Especially my Harley). It's not as cost efficient but they do run better, especially my 25hp outboard gets up on plane faster and has no oil coming out of the hub at all.

He can't get non ethanol without going for a 1 1/2hr drive since he is in New York... Which I recommended earlier but it's a long ride just for some fuel...

So premium is gonna be the best way hands down because at least that way he will get a better burn closer to non ethanol than just regular 87 octane 10% gasohol.

I say non ethanol premium is worth the drive but then again it's only 30 minutes away from my home and i have a contract with that oil company.

Too bad they won't let me get a fleet contract to put regular high sulfur diesel in my old dodge instead of the low sulfur highway crap.

 

[Jay415]

My elevation is sea level. I've been running it on the bay of long island.
Excessive idle could be the culprit. I idle down a canal for about 10 min to the launch, then idle the motor to flush it for a few minutes. Maybe it's the build up that is dripping out.

 

[Buddychrist]

My elevation is sea level. I've been running it on the bay of long island.
Excessive idle could be the culprit. I idle down a canal for about 10 min to the launch, then idle the motor to flush it for a few minutes. Maybe it's the build up that is dripping out.

Turn the idle pin down a hair and give it some premium and see what it does, its just running a little rich and not burning all the fuel.

Also invest in some E3 spark plugs, that will get the spark dead in the center of the cylinder and give you a full burn every time!

 

[Jay415]

I'll try all that. What are E3 plugs? Is that a brand? I've been using NGK

 

[Buddychrist]

E3 are triple prong performance plugs that shoot the spark directly into the cylinder helping get a fuller burn

NGK's are good and that's what I had on my jetski but after I swapped them to E3 it was a nice performance boost and throttle response was greatly increased