It may cause a bog out, you will have to try it now and see.
No, crankcase compression relates to that area between the reeds and the combustion chamber.
Post a video of the sneeze as its often very clear which it is to those who have seen it before.
No worries, its a very good thread, the number of individual views gives you the clue to that!
Hi Bos,
From the pics of plugs do you think to lean, enough to sneeze? Could it be dry due to higher temps now?
I will get a video out. I should have taken it the other day. I will try your fuel check method, just don't have a lanyard.
Appreciate your advice on the thread mate.
I'm trying to work through this in a real methodical way now. I have logged everything for whats become an issue and when, if memory if serving me correct the following may be happening. Please anyone, correct me if I'm wrong.
1. Purchased boat it sneezed a lot then, blow back through port lower carb throat. NO bog out as far as I know. Then again I only ran it once before it all came about.
2. The first lync I did may or not have brought the issue of the bog out into play, as when I read about the three main aspects of lync process. The three parts must be in sync - spark adjustment (timing base), the advance idle screw and the cam roller must be fully inline. I suspect spark adjust is not aligned with the other two - idle screw and roller? As it's the only screw I have never adjusted and have been to scared to do so.
When the throttle cable is pulled the bog seems to occur depending on revs. If not enough revs but put the foot down, the bog would happen. If the throttle is eased into revs in gear slightly the bog wont always occur. If you put your foot down at 1000rpm it will bog.
Could the spark advance cause this issue of bog or sneeze, as when I go high revs there is no problem.
Air idle jet blocked perhaps ?
3. The second lync I performed when the thermos and full carbs pull down occurred at x-mas. The idle advance screw was somewhat higher. This is when I found the brass fitting in the reeds. Sneeze stopped.
4. Third lync where we are now completed pull down of carbs again thoroughly soaked and sprayed on new years. Ran perfect on the Thursday 3/01/19 with the kids, no sneeze, but one or two bog outs.
Saturday 5/01 It ran through rich and suspect fouled plugs (25:1). Sprayed carbs & jets down, replaced two suspect plugs but misfire or sneeze comes back, doesn't happen at higher revs.
5. Port lower has always been the suspect, it is the one with the different looking plug (more oil unburnt). And was found to be the one blowing back through carb throat. So could this be a carby issue, with idle jet?
However, FATZ did say the carb is not inline with the cylinder it serves but is actually in a cross formation. Meaning port lower carb serves the Starboard top piston?
Have completed sync procedure all the way up to the timing light requirement (As I don't have a timing light currently), with cable off.
6. Throttle cable doesn't retract all the way on it's own, may need new cable... I have tried grease the throttle pin but to no avail. The water control valve has made the retraction worse. Throttle doesn't snapped back more than half throttle now on its own. I have tuned the throttle screw eighth direction and doesn't do a lot.
Can this affect the sync?
I must say I have to eighth degree aligned the throat valves up perfectly. The idle mark on the throttle cam is exactly centre of the roller, do you guys have it centred like this also? I want to ensure the advance screw and carbs valves are inline with the throttle....
7. Next phase will be replace all plugs, blow down the passages jets again of the carbs, add some more oil (Bos you think it's a little to dry?), get it in the water and warm up. Adjust the idle advance a little if needed. That's the only items I can see being my issue to adjust.
Now the thermos and water valve is installed, at least the temp is correct now. I can scratch the plugs from oiling up not enough burn temps.
Is there a way determine if it's coils or power pack? The coils look original, power pack seems now CDI type. Or as it can start and go 90ks, can scratch electrical also?
I definitely believe the Faria RPM gauge is out, new prop shows 7k easy (It's not screaming). Could this be an electrical issue at the rectifier sending false reading? May explain way I say it's idle at 1k but could be lower?
Would appreciate any advice if I should go further into other areas.