Adjust valves or pull head?

[nateo]

ok, so some of you may remember my story of spun coupler at wot results in bent valve. Well I'm still having some issues with timing and rpms. When trying to adjust timing I either end up with to low rpm and it stalls or high rpm and high idle. Although it appeared to be running well at the top end the rpms were too high, 4800 instead of 4600 as noted on engine. The starboard side head (which I did not pull) has high compression in one of the cylinders. I believe it was around 169 instead of 150, all others are 150 as they should be. 1. is this likely the source of my high rpm/timing issue? 2. Is this likely just a issue of valves needing to be readjusted properly or might I have some other issue such as a bent or sticky valve?

 

[flipbro]

169psi is ok with the rest being 150. That is not your problem. 4800 rpm is perfect for that engine.. Have you hooked up a vacuum gage yet. Like i stated before you can diagnose bad/ sticking valves. Set timing and and adjust your idle All off vvacuum readings.Do a google search and read up.
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[nateo]

169psi is ok with the rest being 150. That is not your problem. 4800 rpm is perfect for that engine.. Have you hooked up a vacuum gage yet. Like i stated before you can diagnose bad/ sticking valves. Set timing and and adjust your idle All off vacuum readings.Do a google search and read up.
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Today I got it timed and running at 750-800 rpm in idle neutral on muffs. But then I dropped it in water, let engine warm up and rpms were at 800 in idle neutral in the water. It seemed really high so I turned down the idle just a hair and it was too much because it died on me when i put it in gear (and not a kill switch problem, got new shift cable and all adjusted properly). I was thinking it was 650-700 last year regardless if I was in gear or not. Should they be the same or different (neutral vs forward gear). The merc manual is so very vague about setting the timing/idle screw. last year setting the timing on this boat was a snap and everything was to spec. Something doesn't seem right. 800 in water seemed really high. Just seems like it has too much compression. If I retard timing or turn down idle it dies on me.

 

[flipbro]

That is NOT to much compression. 150 169 is a healthy engine. I run 165 170 and idle 700rpms and drops to about 600 in gear.

 

[nateo]

flipbro, so I adjusted the valves today on that head and still getting 160 psi in one cylinder. Plugs was a little wet/oily. Is that indicative of bad oil seal on valve? Debating whether to pull head at that side. Your previous post said 169 ok. If you don't mind me asking, what are your thoughts about the 800 rpm idle neutral? It seemed pretty high to me. Wasn't even sure if I should try putting it in gear.

 

[flipbro]

Nateo how are you adjusting the valves? You should not lose psi when done correctly. Is your tac accurate. 800 is alittle high I would get it to 700rpm idle. The black wet plug could be oil rings or bad valve seals. Does it smoke blue when running? You say you have 150 to 169 psi and able to run 4800 rpm wot just wont idle below 800rpm makese think carb.

 

[nateo]

Thank you for the reply. I'm now thinking I may have a intake leak due to using wrong gasket: http://forums.iboats.com/forum/engi...985293-auto-vs-marine-intake-manifold-gaskets