MS290 will not start

[andrethegiant70]

Sorry if I have been unclear. I know that it is easy to get lost in a long thread like this. Here is the readers digest version of what has happened so far.

1. saw would not start
2. cleaned air filter... no joy
3. replaced plug and fuel filter... no joy
4. replaced fuel line and put a kit in carb
5. started and tuned saw
6. saw ran great and idled for several minutes and then died.
7. saw will start with choke on and dies when I move it to the normal run mode.

I am now planning to go back into the carb for a final cleaning because I suspect that I accidentally left a bit of junk in the carb or that there was something in the new fuel line that washed into the carb.

I will let you know what I find.

My, bad, you're on the right track here. I agree with Fish, there's maybe something getting stuck or there's a bit of FOD in that carb somewhere. I have a Jonsy 2050 that has done that to me. I had it all tuned up and ready to go (I mean running and cutting really nicely) and then I set it down for a spell. When I took it to the woods it wouldn't take the throttle. Zippo. At idle, it purred like a kitten, but no amount of tuning would get the high side working. I haven't dug into it again yet, (my ratty but feakishly reliable 026 has been my little buddy instead) but I suspect some garbage redisolved and blocked a passage or I have crud underneath a welsh plug. The good news for you is that your intake system is REALLY easy to work on... the Swedes must be born with three tiny hands or they always work on a saws in pairs or something.

This sort of thing is a PERFECT application for an ultrasonic cleaner. BTW, I'm convinced you AS guys have been driving up the price on those things!

 

[RAMROD48]

I am pretty sure that compression is fine. I honestly think that it is a carb issue. I did a lot of chipping and scraping to get all the hardened junk out of it. It is very possible that something was left inside. It was also kind of tricky to thread the intake end of the fuel line into the top of the tank. It is possible that I picked up a bit of gunk while doing that. Before I jump to any other possibilities, I want to eliminate this probable issue.

Compressed air is your friend...always try and clean before removing anything...

Yes it is tricky to get the fuel line in, a pair of LONG needle nose will help in this...(doesn't help you now though)...

Maybe just go ahead and deep 6 the carb and get a new one...any pitting in the aluminum surface?

 

[shawn022]

If you go back into the carb pull the limiter caps and remove the needles. If the carb was varnished like you say possibly the passages are partially clogged.

 

[dallypost]

He's Back

Some of you may recall that I was having trouble getting my MS290 running.

After my last posting, we got into summer which means horse training, horse shows and bailing hay. So, I set the saw down and just got back to it.

Here is a quick recap:

Last fall, the saw went from strong to very weak in a few minutes. Since then I have replaced the fuel line, fuel filter, and spark plug. I have also cleaned the spark arrester screen, and the air filter.

Today, I went through the carb one more time and this time I removed the limiter caps and cleaned the needles. The H needle was filthy.

It starts but I have a tough time keeping it going with the air cleaner on. I removed the air cleaner and fired it up. It started fine and tuned pretty easily following the instructions I got on this thread. When I replace the air filter it floods. I held the filter up to my mouth and blew... almost no resistance.

Also, when I first started it with the air cleaner on, it did not want to idle. With the air cleaner off, I had to back the idle screw out a bunch to stop the chain and get a reasonable idle.

I also noticed that at high RPM with the air filter off, fuel vapor is spraying out of the carb. I thought that this night mean that I am running really rich but the exhaust was pretty clean, only smoked a bit during acceleration but not at high RPM, once we got there. Is this normal?

Is this really an air cleaner problem or do I need more carb tuning?

Thanks everyone

 

[dallypost]

Running but not real strong

Okay, I started over and now it idles great. While adjusting H, I slowly turned the needle out until it started loping a bit at full throttle. Now it idles and accelerates good but is a little bit weak when cutting wood. Am I too rich with the H needle? There is a little bit of smoke during acceleration but it is not noticeable while cutting at full throttle.

Thanks