Reed Valves Maybe?

[rshiver]

Hey guys... quick question for some of the pros here. I've got a 89 Johnson GT 200 (J200STLCEB). Recently I've replaced the stator, timer base, power pack, rebuilt all six carbs with kits. The issue I'm having is it will run and idle fine on muffs and runs good on the water from just above idle thru WOT but it will not sit and idle on the water. Got it back home and removed the air silencer cover. When I went to crank it, it would spray gas out of the port side bottom carb. I took the carb off and adjusted the float valve. Went to crank it and the same thing happens, it also tries to spit back from that carb while cranking and while it's idling until it warms up. Also while it's idling I can feel puffs of air coming from the same carb, I don't feel it on the other five carbs. Compression is good on all six cylinders, between 90 and 100 psi. Could the reed valves on that cylinder be bad causing compression to blow back through the carb?

Many Thanks

 

[F_R]

Re: Reed Valves Maybe?

From your description, it certainly sounds like a bad reed. It is the crankcase pressure blowing back, not cylinder compression. No matter the details, it needs to be fixed.

 

[rshiver]

Re: Reed Valves Maybe?

Thanks for the reply F_R...With good compression on that cylinder, I assume it probably is crankcase pressure.

 

[boobie]

Re: Reed Valves Maybe?

The reed block could also be loose on the intake manifold.

 

[daselbee]

Re: Reed Valves Maybe?

I would check that the butterflies are fully closed at idle on the lower two carbs first. They are the only adjustable butterflies, and if one is open slightly, idle will be crappy, and gas will spit out. Not as much as a bad reed, but it does spit out.

The butterflies on all six MUST be closed at idle. Not kinda closed...closed.

That check is free. Checking the reeds is a tough job.

 

[rshiver]

Re: Reed Valves Maybe?

Thanks for the feedback guys. I went ahead and tore it down this morning. On the no.5 cylinder that was spitting the gas had a dime size piece missing from one of the reeds. On three other cylinders, it looked like one of the reeds on each reed box were being pushed through the reed box. The reeds look like they're made from some kind of composite material, not metal like I were expecting.

Now for the nine hundred dollar question... Is it possible to buy just the reeds instead of having to buy the reed box assembly. The reed box assembly I'm finding online are $144.00 each, that adds up to a nice chunk of change for six. I found some reed boxes on ebay but they have the metal reeds for $35.00 each. The sellers descriptionon said they may be factory seconds, or a new, unused item with defects. So what do you guys think?

Reed box on ebay

Also found these

 

[daselbee]

Re: Reed Valves Maybe?

Wellll!!!!!

I have been THERE before!!!! Had the same thing when I used fiberglass reeds. That is the result of backfires on fiberglass reeds.
You can contact Chris Carson Marine in Key Largo to get new glass reeds if you want them.

http://chriscarsonmarine.com/

I went back to the stock metal ones. Those glass reeds are a PITA to have to replace simply because of a backfire.

Good call on the reed damage, FR.

 

[WernerF]

Re: Reed Valves Maybe?

For the photos did you remove the plates that are supposed to prevent the reeds from opening too far?

 

[MACH1SCJ]

Re: Reed Valves Maybe?

They look like two stage reeds, are they? Maby Boyesen's two stage. I was close to buying the two stage but after talking with Chris (very nice & helpfull guy)I got a set from CCMS. If I have a failure after warranty I'll likely go back to the metal ones. I thought you should keep the limiter plates on, I kept mine on.

 

[Faztbullet]

Re: Reed Valves Maybe?

That is Boyesen reeds and is falure from backfires as Daselbee posted, they only last a couple of years in a heavy used fishing motor anyway. Use Chris Crason single stage and you will be fine, just true or sand off the rubber coating on reed blocks.

 

[rshiver]

Re: Reed Valves Maybe?

No limiter plates, that's how they came out. After talking to the local marine mech, think i will be going back with stock metal ones