soot build up on propeller

[bbright]

Last time I took my boat out the engine ran kinda sporadic at low speeds and smoked a lot after starting most of the time. I checked the prop a couple weeks after i took it out last time and there is soot build up on the inside of the propeller, on the brass nut and some on the threads after the nut. I can wipe my finger inside the prop. and get residue on finger. checking my kicker motor it looks clean. Could that have been a result of the abnormal smoking, or does that come natural with larger motors? the engine is a 2002, 125hp mercury 2stroke.. i just bought the boat a couple months ago and they never winterized it, just kept it in a garage.. the main engine seems to be getting worse as far as low rpm performance. What have i got myself into!?? It only has 100 hours on tachometer. It should start up with very little smoke every time right?

 

[bbright]

Re: soot build up on propeller

sorry for not posting this in the propeller forum, move it if you must, any input on the engine is welcome as well.

 

[82RAYSONCRAFT]

Re: soot build up on propeller

bbright,
Welcome to the forums and a new monthly bill. LOL!!!!!
There is alot of information the TEAM MEMBERS here need can provide to you RE your currrent isssues.

2 Strokes run off a combonation of oil & gas premix or oil injection system.
Yes they will smoke mostley if not using Synthetic oil and it is not uncommon. Nothing to do with the size of the motor but the design(2 stroke fire every stroke of the piston per thier design)
If you don't have a basic manual then get one and it will help U on understand some of the basics.(not being a smart A$$)
With past experience on 2 stroke engines nothing seems to idle/start right.

Then again I've only owned the HIGHER HP stuff.

Anyone else??????????

 

[WillyBWright]

Re: soot build up on propeller

Welcome to iboats.

You posted in the right place.

If the motor is idled a lot, you'll get that. Have a look at how the sparkplugs are burning. If they're all sooty too, there's a problem. Ideal deposits are dark brown and slightly damp-looking.

Now for the low speed issues. Probably normal. At idle, it runs on the top two cylinders. Above 1/4 throttle or so the lower two kick in. At about 1/4 throttle it has a hard time deciding to run on 2, 3, or all 4 cylinders. That's usually between 1800 and 2400 RPMs. To avoid that, either run below 1800 or above 2400. If you have a beginnner waterskier or a wakeboarder, my sympathies. Those are lousy motors for that. It's about impossible to keep a constant speed for them. But for most other waterskiing they're fine.

 

[tashasdaddy]

Re: soot build up on propeller

not knowing history of the engine, i'd do a decarb. cheap and sure won't hurt anything, only make it cleaner.

http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1035563

 

[Laddies]

Re: soot build up on propeller

Your engine idles on 2 cyls so the soot is nornal if you idle a lot as it picks up 4 as the RPM increases

 

[bbright]

Re: soot build up on propeller

grrr.. i just lost a big paragraph my pressing enter and an error popped out. Anyway thanks for the input, i thought it was kinda funny my old 1967 40hp johnson ran smoother at slow speed but theres a big difference in engines and mine might be running so bad after all. I did put some sea foam in the gas and it seemed to help overall performance. I thought about decarbing and i have all the stuff just waiting on a repair and maintenance manual before i start. I've found a few good posts on this site about decarbing and it doesn't sound like i can mess anything up too bad.

One thing that has been kinda bugging me is the throttle. It skips a beat, i get to about 4 mph smoothly and responding well, then continuing to accelerate nothing happens, until I get to a certain spot and it kicks in planing me out but i still cant gradually take off. i figure a little adjusting on the throttle cable might work but does anyone have any input on this?? thanks again.

 

[Laddies]

Re: soot build up on propeller

The skip is when it's starting to pickup the other 2 cyl. In some cases you can help the problem with a low speed carb adjustment and synchronization