Intermediate and WOT issues with 850 4 cylinder....flooding?

[centerline]

OK, that serial number looks to be a 4 cylinder Merc 850, from 1975. Spark Plugs should be NGK BUHW. Remove, clean and rebuild the carbs with new gaskets, floats, inlet needles and seats, or at least inspect them to make sure the mechanic did it.

Invert the carb bowl cover and see if the float levers are parallel with the cover. That is the proper adjustment. Make sure the float is hard plastic and has the little spring on top. Clean or replace the banjo filter in the cover over the carb bowl cover.

Initial idle mixture adjustment is 1-1/2 turns open. Final mixture must be set on the water, at idle, warm engine, fresh fuel mixture.

It probably makes sense to get a service manual, so you can check the timing as well.

the sparkPlugs are NGK BUHW..
I have a seloc service manual... as decent as I thought seloc was, the seloc manual for my 4.5hp has very confusing/wrong information in it about the 4.5... I will be finding out how the manual for the 850 works for me...

 

[centerline]

What did the mechanic say about the ----" top end noise " ---Did he have any idea ?----Did he do any inspection looking for this noise on a new looking motor ?

he had no idea about the noise, but said it sounded like it needs rebuilt... he scoped the cylinders to look for scoring and checked the compression while I was there, so I know he did that, and it all checks out good.....

even with the boat running as bad as it does, we used it quite a bit last summer (between the times the mechanic was working on it)... my thought was that im GOING to use the boat to the best of its ability, and if its going to blow up, let'er blow, as that will be a good excuse to bolt something different on... but it hasnt blown up so it must be ok, and another summer is coming so I just as well get it running right before we want to go boating again... so rather than idling around the lake, we can scoot along a bit faster.

 

[centerline]

Restrictors..... They melt and get sucked through the enigne. When they're gone, you get the problems you have....

I was just reading about the symptoms plugged restrictors could cause last night. I didnt read anything about the lack of them... and I still dont know where the restrictors would be. or should be located... or what they look like if I see them..

 

[achris]

They are basically an oil return circuit for pooled 2 stroke oil. The later V6s have them as hoses and valves around the engine, passing oil from the transfer port of one cylinder to the intake side of another. On the early in-lines (4 and 6) they are just 'bleed holes' located under the transfer port covers on the starboard side of the engine, in the bottom corner of the port passage. You need to pull the transfer port covers off.

Chris....

 

[Faztbullet]

The bleed restrictors have nothing to do with oiling. On a inline at idle the fuel will puddle in the corner of transfer port due to block casting, What happens if restrictors are missing is fuel puddles and when boat is accelerated it dumps slug of raw fuel down passageway and fouls the plug for a millisecond causing a stutter and miss, they will not cause it to die just shifting into gear. Usually dying when put in gear is worn labyrinth seals on reed blocks, coupled with noisy upper end sounds like a teardown is needed.