87 blackmax poppet valve adjustment?

[jigmister]

175 hp blackmax.

every so often when the boat comes off pad from a short run the temprature gage falls to cold and engine idle becomes rough. Engine sneezes a time or two and may even die. It acts exactly like it dose on the fisrt start of the day in the cold morning. Warm the engine back up and all is well.

I replaced all the reeds with chris carson reeds and lapped the reed blocks. Rebuilt all the carbs and installed new needle and seats. New thermostats as I figured one may be staying open.

The cold running problem was present before and after the work.

poppet vavle was replaced not too long ago.

I got to thinking that the spring tension on the vavle may not be enough thus allowing cooling water to bypass the thermostats at too low of a water pressure.
I noticed a screw on the poppet that appears to adjust the spring tension.

am I on the right track here?

thanks for any help

Jim

 

[aussieflash]

Re: 87 blackmax poppet valve adjustment?

Are you saying its cold on plane and warms up when idling?I replaced both tstats and cant get it to run warm on plane,only at idle and low speed.Havnt checked poppet yet.Running V6 88 model.Sorry im also stuck on this.

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

no
it warm on plane. when coming off plane it cools down very fast. by the time I am off pad and idling its COLD. You can watch the gage needle drop like a stone thrown over board
I am asking if there is a poppet vavle adjustment.

 

[Faztbullet]

Re: 87 blackmax poppet valve adjustment?

No adjustment to poppet, sound like it may be binding in block seal.

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

when on the hose at the house to flush I see water dribbling from the tiny hole on the poppet. Is this normal?

 

[Faztbullet]

Re: 87 blackmax poppet valve adjustment?

Nope...replace diaphram

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

new gaskets and diaphram on the way. However the diaphram appears good with not holes and was replaced not too long ago. The water has been weeping out of the hole before and after replacment.
when the valve opens where dose it allow the water to exit to?
I think somthing may be restricted or blocked or otherwise not allowing the water to pass.

I also noticed a very small dripple coming from here

thaks for any ideas

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

ran her today. idle is ok when warm. but again come off plane and the temps fall to less than 1/4 the gage. dies and sneezes.

any ideas? this is killing me. should I go ahead and pull the powerhead and change the gasket? could that be the problem? look at above picture

 

[sschefer]

Re: 87 blackmax poppet valve adjustment?

A while back there were a bunch of bad poppets that were floating around. It looked to me like the ends were cut at an angle causing them to hang on the grommet in the block. I had three of them in a row. If you have the blue poppet from Sierra check the alignment with the diaphram installed and make sure it's square to the valve.

If you installed the new diaphram incorrectly it will leak water out the weep hole. That hole is a pressure relief for air not water. Get your factory shop manual out and review the proper assembly in the parts list. If you don't have the manual you can refer to the parts list at www.crowleymarine.com

Added thought.... Your motor should be running between 130 and 140. Idle temp is around 125 on a cold day and 135 on a warm one. Temps shouldn't go above 145 at speed if the cooling system is working correctly.

If your running a water pressure gauge you should see the poppet open at between 1300 and 1700 rpm. The pressure will rise then fall off and build back again as rpms increase. The pressure guage should be fairly steady. If it's bouncing all over the place then it's usually the poppet.

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

anyone know what that leak is about?

 

[jigmister]

Re: 87 blackmax poppet valve adjustment?

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