Thread: engine still misses over 2600 rpm

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Hello Everyone:
I still havn't resolved my problem with my boat engine. Let me bring all up todate.
Removed head, shop fixed 2 tuliped valves. Adjusted valves cold, several times. Didn't want the mess in my boat to adjust while running but not sure they are right.
Engine run good up until about 2500 rpm's, has no more after that. Checked all cylinders by pulling plugs wire off, while running , they all seem to be firing ok. You can hear a little popping out the exhaust.
What steps should I take to resolve?

Thanks to all for your help
leonard

I suspect the valves are too tight. Go to www.summitracing.com and order the oil deflector clips under part number SUM140355. They will allow you to adjust the valves while the motor is running, but without splashing oil all over. Lay down some plastic to keep everything clean. You can even use the plastic from the dry cleaners that they send your clothes home in.

You can adjust the valves as follows: Start at #1 rotate engine over until a valve opens (int or exh) and adjust the one that is closed to zero (where the pushrod just gets tight) then rotate and adjust the other one, do this this for all cylinders then take them all half a turn.

Thanks for the replies.

I ordered the clips from summit. Will be doing it while running. There are so many different ways of doing it cold. I guess if you do it enought, you get the feel for it, but weekend mechanics like myself don't know which way is correct.
thanks
will post my results, after I get the clips and adjust them.
leonard

One thing about the clips, don't rev the engine too much, they'll come off. I've still got one missing in my garage somewhere.

I cut a window in the top of an old valve cover to cut down on the oil splatter too.

Well I adjusted the valves while running with the clips from summitt, no mess, thanks to all.
This seem to really help, found valves too tight. Thought I had the problem licked, untied the dock lines for a test, ran better, but the engine would cought thrugh the carb. You could feel the engine run good than start missing, run good than miss. I guess is electrical but what do you guys think?
I really like chatting with you guys on this forum.
thanks
leonard

sounds like you may have to much timming in the motor. i know that it's alittle hard to hear the engine in the boat, but can you here any pinging from the eng ? while you are under way. you can start off by setting the timming to 0, and then advance the timming up slowly and try it
. and see if it helps any. if you go too much you will feel it in the performance at the top end of the run\2500 + good luck let us know how it turns out.dave

Hi WRENCHD:

Thanks for the reply. There is some slight pinging but what's throwing me off is you can feel the engine smooth right out and then it sounds like she is missing on at least 2 cylinders. i've have ordered new plugs, dist cap, and point and condensor. I put new in last year, & also new wires. She runs perfect at idle.
Will check the timing.
leonard

If at all possible save some money and get rid of the points and condenser and go to an electronic ignition with a 40 kV coil or so. You will be amazed at the perfromance difference.

Kitz

I think that it is time to begin investigating the carburetor.

Do you know the fuel pressure at the carb inlet?

i agree that you should install a hei dist,(should be able to get one at the scrap yard cheap. also did the shop put in valve spring shims when they did the head work?. the rest of the info the other guys stated is also needed good luck and let us know how everything turns out.

Hello:
Thanks everyone for their replys. I wish is it was as simple as the carb. If you guys think it's the carb , I will switch them this weekend and see if the problem moves to the other engine. I have twin engines. The engine seems to be running rich by the fylm on the side of the boat, but that might have been the valves out of adjustment.
thanks all
leonard

Hello Denny:

You may be right about them being jealous. The fuel lines run from the indiviual tank to a filter then to the carb with a line between the 2 filters. Do you not think the problem is electrical? The engine will run smooth for a few seconds then it sounds as if she has lost some cylinders, rpm's will drop, and just nothing more after 2600 rpm's.
thanks
leonard

Hello Denny:
There are 2 tanks, 1 for the right & 1 for the left feeding a filter than to the carb on the left and the same for the right, tank, filter than carb/engine and a line between the 2 filters. I hope this explains it better. This is how it came from Sea Ray. What makes you think the problem is fuel?
thanks
leonard