94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

[leisjohn]

I can get it idle if I set the timing to about 4 BTDC. It will idle for a few seconds on the hose but not in the water.The engine has NOT been run in the water in about 3.5 years. I just ordered the carb rebuild kits. Any ideas out there of other things I need to check.

 

[metriccrescentwrench]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Check compression. Make sure there's good spark on all cylinders (spec is for spark to jump 7/16" on a spark tester). If those are good then you're probably on the right track with the carb rebuild kits.

 

[leisjohn]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Compression is good and so is the spark. Someone said to check the recirculation fittings to ensure they are not blocked. What do you think? The idle timing is important correct?

 

[dingbat]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

What is your idle set at?

 

[daselbee]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

If spark and compression are good, it will idle at 4* atdc with all butterflies closed. So, seeing that it doesn't, I would be looking at the idle circuit fuel feed. In each carb, there is a small brass tube that extends down into the bowl. That is the source for idle fuel to the engine. Make sure all tubes are clear, follow circuit thru the side labyrinth chamber behind that metal plate and clean accordingly, follow circuit on through to the throttle bodies, and clean behind the core plugs. That is the idle circuit. Another thing I do is when running at 2k rpm or so, I clamp my hand over the mouth of each carb sealing it off completely, for a second or so. When you remove your hand, if carbs are working right, raw gas should pour out the front of the carb throat. All cyls should respond the same way. If you have a carb that does not pour gas out, then look at the center ring of the bowl gasket for air leaks there.

 

[leisjohn]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Thanks a lot guys!
Dingbat, to answer your question, the timing is about 1 or 2 BTDC in order to get it to idle, Even then it's not very smooth and not able to adjust the carbs to smooth it out.

Daselbee, The core plugs look like small freeze plugs in the side of the throttle bodies, correct? What is the recommended way of removal? The core plugs don't come with the carb kits so I will order them? have you ever heard of the recirculation fittings or check valve causing a no idle condition? All 6 do pour gas out when chocked at 2K. The carb kits should be here Thursday so Friday evening and Saturday will be spent rebuilding them and if all goes well maybe float test on Sunday.

 

[daselbee]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Yes the core plugs are on the side of the throttle body, about 3/8 or so in diameter, maybe 7/16. The way to remove is drill hole, thread sheet metal screw in, and pull/pry out with pliers. To install, place new core plug, center 1/4" socket extension on plug, hit with hammer to dent in the center of plug slightly. This expands the diameter of the plug, locking it in place. The core plugs come with the carb kits. Behind those core plugs are very tiny holes. Make sure those are clear thru to the throttle bore of the throttle body. You will see if you inspect very closely. The brass tubes in the carb taper at the top where they press into the plastic. They are tough to clean properly. I use long reach welding tip cleaners to get all those holes.

I have purposely clamped OFF the recirc valve lines to simulate a blockage. I have also purposely pulled lines off to simulate a cracked line. NEITHER condition caused any noticible idle issues. I have not done all 6 at once, tho.

 

[dingbat]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Thanks a lot guys!
Dingbat, to answer your question, the timing is about 1 or 2 BTDC in order to get it to idle, Even then it's not very smooth and not able to adjust the carbs to smooth it out.

Idle RPM.....

 

[leisjohn]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Great thanks so much. I've rebuilt the boat from the hull up and now my only obstacle before I can get off shore and do some fishing is getting this engine problem figured out. Project turned out to WAY larger then I first expected but, it will be worth all the work. I'll check back in after I get done rebuilding the carbs and testing it. Again many thanks for the ideas and information.

John Leis, Ft. Pierce FL.
Fair winds and following seas!

 

[leisjohn]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Dingbat,
about 950

 

[leisjohn]

Re: 94 Johnson 200 Ocean Runner won't idle when timing set 4 ATDC per manual

Hey guys,
I got all the carbs & throttle body cleaned. Wow, it has never idled better. Thanks again for all you help.