1976 70 Johnny, totally frustrating.

[tashasdaddy]

what am i missing, carb clean rebuilt with kits, spark 7/16 by tester, compression 125-130 range, timing perfect, link n sinc, new plug wires. cannot get it to fire one middle and bottom. runs on top cylinder only. the only thing i have not done is pull the intake. it is a fuel problem, middle plug dry, bottom black and sooty. top burning beautiful.

 

[wilde1j]

Re: 1976 70 Johnny, totally frustrating.

Rare, but a reed valve problem?

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

seriously considering that, even sprayed starting fluid in those carbs and nothing. yes, i was desparate.

 

[Blade_Link]

Re: 1976 70 Johnny, totally frustrating.

sounds like a reed valve or your fuel lines are getting worn id check your whole fuel system

 

[tx1961whaler]

Re: 1976 70 Johnny, totally frustrating.

New plugs?

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

fuel system good, carb bowls full, plugs were new yesterday, bottom sooted now. middle dry, top runs. gapped .030 QL77JC4's

 

[wilde1j]

Re: 1976 70 Johnny, totally frustrating.

I would take a look at the reed block ... nothing to lose at this point.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

going there today. anyone else?

 

[jay_merrill]

Re: 1976 70 Johnny, totally frustrating.

You sprayed what into it?

Dang, TD - you really must have been frustrated!

Did you get 7/16ths spark on all three consistently? It almost sounds like a combination problem, with fuel delivery on the dry plug and ignition on the wet plug, but consistent spark would rule out the ignition possibility.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

showing great spark on the gapped tester, all 3, compression checks out great, pulled carbs this morning, reeds look clean and spotless, all move with pencil eraser. even did the celephane test. where you put cling wrap over the opening, the rotate flywheel by hand to see if you get suction, all 3 looked to be sucking the same. i am temped to put the starter back on it and put fuel directly into the reeds and see what happens.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

OK really stumped now. tried the ole fuel directly into the reeds, fire up on # 1 without a carb, #2 & 3 not a peep.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

rearranged coils same thing, #1 will run, 2,3 no go.

 

[F_R]

Re: 1976 70 Johnny, totally frustrating.

rearranged coils same thing, #1 will run, 2,3 no go.

Um, I was about to suggest #2&3 coil wires switcheroo'd on the power pack, but I guess you would have caught that.

 

[Joe Reeves]

Re: 1976 70 Johnny, totally frustrating.

You have 14 psi difference between the highest and lowest compression reading..... Not Good!

A black sooty spark plug apparence indicates weak ignition, however you state that the spark is great and jumps a 7/16" gap? Jumping a 7/16" gap is outstanding.

Make sure that the carburetors are clean and that the fixed high speed jets located in the bottom center of the float chambers are absolutely clean.

It would be an excellent idea to remove the cylinder head in order to inspect the head gasket, piston and cylinder wall apearance, and the sealing surfaces of the head and crankcase (block) before going any further.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

F_R you are a genius!!!!!!! firing all 3. why i never thought of that.

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

Joe, the compression was a type, 125 -130. the reason i spray directly into the reeds, was the carbs were already off.

it ran like a champ, until, the tstat did not open. either blew head gasket of lost #1 cylinder. will break it down in a couple of days.

 

[jay_merrill]

Re: 1976 70 Johnny, totally frustrating.

What am I missing here - a 1976 Johnson 70hp motor with a rotor and points?

 

[tashasdaddy]

Re: 1976 70 Johnny, totally frustrating.

it is stator and power pack.


no wonder i got it for almost nothing.
head gasket is horrible, water passages full of sand, gravel, salt.

no signs on piston head of ring coming apart. cylinders are clean an smooth.

looks like head gasket, water jacket to come off head, new gaskets.

 

[seahorse5]

Re: 1976 70 Johnny, totally frustrating.

Bad gasket behind the intake manifold can give a similar symptom. Reeds may look good but you have to remove the plate and reeds to see the gasket condition.

A scored cylinder also can give good compression. Do a leakdown test on each to be sure of their condition.

Paint a mark on the flywheel at #2 and #3 TDC and when you run it again, check each spark with a timing lite to see if it fires at the appropriate mark.

 

[Joe Reeves]

Re: 1976 70 Johnny, totally frustrating.

Jay Merrill....... The rotor and dist cap thing. My boo boo! I was typing to a couple other posts and got sidetracked, confused, and totally discombopulated (whatever the hell that is). I'll edit it out. Makes me wonder what I entered as a reply on that 1970 Battery Capacitance Discharge 85hp engine elsewhere. Oh well, just turned 77 on Aug 6, I'm going to blame it on age.