1984 mcm140 won’t go above 3000 rpms

[chopper6322]

So I have a 1984 MCM 140 sn 6720563 last weekend the boat would not start all after being parked at a swimming hole for an hour or so, came up with no spark so I changed out my plugs, wires, points, condenser, and distributor cap and rotor (all were a bit old so I didn’t try and figure out which part was bad). Anyway set the dwell and the timing. Took it to the lake today and it started great but would not get above 3000 rpms and had an occasional backfire...did I mess up the timing? Or just run into a new issue?

 

[Scott Danforth]

check your timing, however could also be dirty carb.

 

[chopper6322]

None of my plugs or wires are labeled, I’m sure I put them back on how they were but am I correct in thinking the forward most cylinder is the number 1???

 

[Scott Danforth]

None of my plugs or wires are labeled, I’m sure I put them back on how they were but am I correct in thinking the forward most cylinder is the number 1???

not always. you need to bring the motor up to TDC on compression stroke on cylinder number 1, then look where the rotor is pointed. however on the motor, if you have your plugs wired wrong, it would shake like a dog passing a porcupine backwards

 

[Scott Danforth]

by the way, what was the dwell that you were at? 28-30 degrees?

 

[chopper6322]

Yes the dwell is 28-34 but I will check that again to make sure nothing moved. I saw the sticky on finding top dead center but wasn’t sure which cylinder was actually the number 1 cylinder to check it

 

[Tycer]

Keep in mind points rubbing blocks can change shape quick in the first few hours. Even more so if you don’t lube the distributor lobes. Scott is correct. Recheck everything then rebuild your carb if all is still set properly. Be sure to check dwell at both idle and fast idle. If the fast idle reading fluctuates your distributor bushings are worn. Mike’s has a great ‘tube video tutorial on rebuilding the Mercarb.

 

[chopper6322]

I did not check it at fast idle so as soon as the rain stops I’ll get after it and report back, thanks guys

 

[chopper6322]

Alright, the dwell was out, so I reset it to 32* but when I go up to about 1200 rpms it drops to 24* does this mean a new distributor or can it be reworked to replace those bushings? Also on my timing plate it has 2-8-4 before and 2–8-4 after and the timing is suppose to be 6* before. Is the 6 between the 2 and the 8 or between the 4 and the 8?

 

[Scott Danforth]

each tick should be 2 degrees starting at 0. numbers dont jump order. I bet that 8 you are seeing is a 3

grab the distributor shaft and wiggle it. if it moves, pull the dizzy, go to napa, spend $5 on new distributor bushings.

 

[chopper6322]

It moves vertically but not from side to side at all, is the vertical movement what you mean?

 

[chopper6322]

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