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I have a 550ex I’ve been tinkering with and I can’t get it started. When I got it it had grey oil but I couldn’t smell gas and it wasn’t over filled. When I first took the filter off and sprayed some carb cleaner it gave a small putter (but not close to running). so I cleaned the carburetor (but I never did take the plastic Jett assembly out) and fresh fuel but now I cant even get a sputter. It had a brand new plug and I know it’s getting spark from the coil. It has 50psi of compression which I know is kinda low but wasn’t sure if there’s a pressure release when staring making it lower then your average engine. I checked the flywheel key and it’s not sheered. Does any one know if it’s valves or something I’m over looking?

Please post the model numbers so we have a better idea of what engine you are talking about.

On that engine the most likely cause is going to be the jet assembly is your problem. You can attempt to disassemble and clean the jets or purchase a new assembly. I’ve had about a 75% good results in cleaning them, but if I don’t like the looks of it on disassembly I replace them. There are a couple of U-tube videos on how to do it, but be careful who’s advice you follow.

Here is a service bulletin on these carburetor modules. Show how to remove the module and installation.

DSB-1060

StarTech said:

Here is a service bulletin on these carburetor modules. Show how to remove the module and installation.

DSB-1060

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Will this help even with my issues of not getting any sputters with starting fluid when I try starting it?

Dustyman said:

Will this help even with my issues of not getting any sputters with starting fluid when I try starting it?

Click to expand...

The simple answer is no. It was posted in reference to removing carburetor jet assembly.

In order to engine to run you must have fuel (starting fluid counts as fuel in this case), air, compression, and spark at the right time. Since the flywheel was intact and you have 50 psi compression, air and fuel then you may a failing spark plug under compression or lost of spark under compression. A good to eliminate the spark plug is to try a known good plug, new don't always mean good.

StarTech said:

The simple answer is no. It was posted in reference to removing carburetor jet assembly.

In order to engine to run you must have fuel (starting fluid counts as fuel in this case), air, compression, and spark at the right time. Since the flywheel was intact and you have 50 psi compression, air and fuel then you may a failing spark plug under compression or lost of spark under compression. A good to eliminate the spark plug is to try a known good plug, new don't always mean good.

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It came with a new one. I just baught a new one. Still no luck. Could my coil be failing? My wife told me there was light when I used the spark tester but I don’t know how bright it was.

Dustyman said:

It came with a new one. I just baught a new one. Still no luck. Could my coil be failing? My wife told me there was light when I used the spark tester but I don’t know how bright it was.

Click to expand...

Some swear by these little neon lights but I don't use them knowing they only indicate the present of high voltage but not the strength of it. For most engines it take around 12,000 volts to jump the plug gap on a cold plug; less when it its hot. This why I use a spark gap tester here set at .166" gap when it grounded.

Personally I don't like having someone just buying parts just to find it is not the problem. Since it appears you have limited experience with working with engines I would recommend finding a confident mechanic that troubleshoot the problem locally. What you got to remember is we are not there to see the problem ourselves and can be missing something simple by trying to troubleshoot a problem remotely.

I had too many customers to spend a lot on parts to only find out later it was something simple everybody was overlooking. There is no shame in admitting you need help, its when you don't the shame comes in play. Asking for help just indicates that you know you need help and willing to admit it even the best mechanic will ask for at times when they get struck on a problem. I have been working professionally on equipment since '79 and I still ask for help at times.

I working on currently a finishing mower where one of the problem was one the swivel wheels was hanging up when the customer picked up deck. He wanted me to replace it. A fairly expensive part considering it is a Bush Hog brand mower. I was checking it out today and it turned someone had used a pipe wrench on it knurling the shaft. A little filing in the right spots fix that problem. Now if I can only get all that hi tack chainsaw bar lube out of the gear box before I replace the failed oil seal. What a mess.

50 psi compression is concerning. chances are the exaust valve is rusted and stuck open