Sticking valve?

[bigbob_FTW]

All i get when i try to start is a backfire thru the carb. Rebuilt the carb, and did a complete tuneup. Its getting spark and gas, just won't start. This boat sat for a long time. Did a compression check and the only thing amis was number 4 was about 10 psi lower than the rest (130 to 120). could this be a stuck valve? I think I'll pull the valve cover next.

ok more info. The engine sticker says ccw rotation, but when I look at the h/b its spinning cw as is the distributor. This engine is all original, so is there any way the starter can spin backwards, or am i just nuts?

 

[Silvertip]

Re: Sticking valve?

Since you said you did a complete tune-up, did you perhaps screw up the firing order (plug wires on the wrong plugs or in the wrong places on the cap). How about timing and dwell?

 

[bigbob_FTW]

Re: Sticking valve?

I want to go back and set up to TDC, but I need to know if the rotation is incorrect. Anything is possible at this point.

 

[bigbob_FTW]

Re: Sticking valve?

ttt

 

[buggiedad_67]

Re: Sticking valve?

if i member right the ccw means looking at flywheel from rear turns ccw, looking from front it turns cw as does the dist, make sure you have the right fireing order, check point gap. if that doesnt work then pull valve cover and check valves,

 

[bigbob_FTW]

Re: Sticking valve?

Thanks for the reply. I'm going to start from scratch and make sure all the timing is right, then move on to the valves.

 

[jerryjerry05]

Re: Sticking valve?

Sounds like the rotation is correct.Make sure you have the wires on right. 5-10# wont hurt. If you are getting spark maybe your 180 out.
AS you look straight on at dist.#1 should be on rhs 2/3 way down on right.( I think) You chances of the valve needing adjusting just don't seem right. Something you missed I'll bet.Jerry

 

[bigbob_FTW]

Re: Sticking valve?

Sounds like the rotation is correct.Make sure you have the wires on right. 5-10# wont hurt. If you are getting spark maybe your 180 out.
AS you look straight on at dist.#1 should be on rhs 2/3 way down on right.( I think) You chances of the valve needing adjusting just don't seem right. Something you missed I'll bet.Jerry

Your post gave me the hint I needed. I remember the #1 wire always in the position you describe, so i set #1 at TDC and the rotor is pointing at the number 3 tower. I go to pull the rotor off, and low and behold, it spins 360 deg on the shaft. I don't know how, but there is a groove thru the gusset inside the rotor (its oem mercruiser, but still made in china). Will get a new one tomorrow and try again. I'm certain this was the problem, thanks for the tip!