1992 200HP Mercury offshore popitt valve question?

[jdupree]

Motor is running warm /almost hot between 1500 to 2000 rpm's. It is cool at idle and fine running WOT. Once I come down from WOT is when the temp starts to rise. Water pump and t-stats have been replaced within the last year. I have had this problem for many seasons but have yet to figure it out. Could this possibly be a popitt valve issue? Any advice would be appreciated!

 

[j_martin]

Re: 1992 200HP Mercury offshore popitt valve question?

When the poppet closes (on the way down) at about 2000 or 2500 rpm , I would expect the temp to rise, maybe considerably if the metal is good and warm from a hard run. As long as it doesn't actually overheat, I wouldn't worry about it.

 

[jdupree]

Re: 1992 200HP Mercury offshore popitt valve question?

I feel sure that it will overheat if I keep the throttle around 1500 to 1800rpm's. I do have a water pressure gauge and what kind of psi should I have at those rpm's?

 

[sxmerc]

Re: 1992 200HP Mercury offshore popitt valve question?

You shouldn't see more than 3 p.s.i. at those speeds.

 

[j_martin]

Re: 1992 200HP Mercury offshore popitt valve question?

I feel sure that it will overheat if I keep the throttle around 1500 to 1800rpm's. I do have a water pressure gauge and what kind of psi should I have at those rpm's?

Usually you have enough to get it off the 2 lb peg at idle, maybe 3-5 lbs, then it ramps up to around 10 or 12 at 2000 - 2500 rpm. Then it'll step back a couple of lbs when the poppet opens up, and should ramp up to 15 - 20 lbs at wot, maybe a little less if you're running high and sucking a bit of air now and then.

If you're running 3 lbs at 1800 rpm, you need to either fix the cooling system or get the motor in the lake.

hope it helps
John

 

[Faztbullet]

Re: 1992 200HP Mercury offshore popitt valve question?

Check for stuck poppit or debris under it....

 

[jdupree]

Re: 1992 200HP Mercury offshore popitt valve question?

Any trick to removing and checking the poppit valve? Compression is great on the motor and the t-stats and water pump have been replaced within the last year. Was just trying to figure out what would be left to check?

 

[ufm82]

Re: 1992 200HP Mercury offshore popitt valve question?

Remove the top cowling and split the lower cowling for access. The poppet housing is on the starboard side at the bottom of the block. Once the cowling is out of the way, the poppet is easy to get to. I did mine after eating a bunch of sand and clogging it. I'm having a similar issue with my 150 right now but mine runs hot at 3,000 rpm. Still working to resolve that issue...