78 johnson 175 wet plugs only turning 4200 rpm

[Skools Out]

have you checked your timing?

[Orlando]

checked the idle timing, havnt had help to check wot timing yet, but the stop looks like its never been touched. will run the gauntlet today and get my wife to help, shes about as good with anything on wheels or with moving parts as my two year old son. so hopefully i'll have enough fingers left to type the results later on.

[Orlando]

probably do a seafoam decarb as well, although im pretty sure it dont need it, got to put the boat in the water today anyways to fix some rollers on the trailer. gonna get another set of new spark plugs too, decarb and use the two month old ones as spares. the compression seems a bit low, even if it is even between all cylinders. so a decarb couldnt hurt i guess. i'll do the timing on muffs without starting engine, that should eliminate the odds of my wifes driving throwing me overboard.

[Orlando]

ok, time for an update. timing checked out ok, did a decarb and changed plugs, no difference except my compression came up to between 97 and 105 psi per cylinder, or might just be i was using a different gauge.but no improvement in running

[Orlando]

ok, just noticed i got a little water leaking around the outside of one of the head gaskets, not much just a very slow drip, maybe one drop every 8-10 seconds. but compression is good. i changed that head gasket a couple weeks ago, so probably get by with just tightening it up a touch.

[Orlando]

just changed the oil in the lower unit, nothing looked amiss. got one idea left, this engine has fixed high speed jets from what ive been told, but could the low speed jets be pumping out to much fuel causing my symptoms? and are they adjustable?

[brisboats]

Check the timing advance, it maybe hanging up if the motor has ever sat for some time. I doubt your low speed jest are pumpng to much fuel. Tach going haywire is usually a bad rectifier, your tach reading of 4200 may be wrong as well if the pulses are set incorrectly.

B