70 horse with dead hole ?

[Carpfisher]

Still working on my 92 johnson 70. Lowerr unit is all sorted out. Starts right up and idles ok with muffs at home and in the water, but when I put it in gear, it holds idle but stalls. restarts OK at first but then seems to load up and not want to restart even when trying to clear with WOT. Does restart though when manually enrichening the start solenoid. I know theres a problem with the actuation circuit and I will address that but I found a bigger fish to fry first !!!

Back at home, compression check shows 108 on #1,112 in middle and 106 at the bottom. Yes WOT.and I've already done the seafoam thing which helped bring it up from the "crap, I shouldn't of bought this thing, under 100 readings "

So I'm in it for a few nickels and feel I'm close, oh so close...

When I have it idling on muffs and pull a wire one at a time, top 2 make a noticeable difference, bottom cyl is a dead hole, no change.

Deffinitely have spark, fat at the plug, not coil or wire, switched with middle cal, still no change.

Sprayed some carb cleaner and it didn't seem to help, not in any of the cyls, it was berry mans, maybe not flammable?, we use brake clean at work and I know that stuff burns, anyway, my current path is carb/reed related, plan on pulling the bottom carb this AM. What am I looking for when I look at the reeds through the intake. It looks like I have to pull the manifold to completely access them. I take it they should be "sprung" closed. Looks like I'm looking for a completely gummed up, clogged carb and/or bent,broken cracked or sprung reeds ?

Any other thoughts ? If there was a problem with the bottom powerhead gasket?, would that cause a dead hole and if so, would(n't) it be from a lack of compression, which I know is low but Is there ?

Thanks
Carpfisher

 

[Joe Reeves]

Re: 70 horse with dead hole ?

From what you've said (You have comp & spark), you have either a fouled carburetor or a broken leaf valve on the reed plate.

Yes, the intake manifold needs to be removed to properly access (view) the reed plate assemblies. And yes, the leaf valves should be sprung closed upon the plate.

 

[Carpfisher]

Re: 70 horse with dead hole ?

Thanks Joe, Carb was clean. Looking at the reeds from the carb side, the middle-all 6 completely shut, bottom problem carb- 2 of the 6, lower on the strbrd side are not shut. Top one also has 2 not closed all the way, but that cylinder had power, so not sure the incomplete closer is the problem. Put back together and gonna try the power drop test again, this shutting off power to the coil by pulling the incoming power wire to the coil instead of pulling the plug wires.

The manual says "The base of the powerhead and lower crankshaft seal is impossible to check on an installed powerhead. When every test and system have been checked out and the bottom cal seems to be affecting performance, then the lower seal should be tested."

If the lower seal is really bad, could my fuel charge be escaping there instead of entering the port ? Could that be the problem ? Would it also effect upper cylinders or just the bottom ?
Or do the reeds have to be COMPLETELY shut for the fuel charge to enter the port instead of be pushed past the carb ?

Should have the cylinder drop test done in a few.
Thanks again for your help.

 

[Joe Reeves]

Re: 70 horse with dead hole ?

Although the carburetor looks clean...... the brass high speed jet is located in the bottom center portion of the float chamber and has been known to foul and clog quite bad. If you haven't visually checked that item, do so as fuel must flow thru that jet before it can gain access to any other fuel passageway. I always carefully clean them with a piece of single strand steel wire as cleaning solvent just doesn't do a proper job on that item.

The leaf valves don't necessarily need to be completely shut flat on the reed box but it is preferred. Crankcase pressure normally forces them shut as the piston comes down... It just depends on how much clearance is between the leaf valve and the reed box.

With the carburetor face plate removed and the engine running, I strongly suspect that inserting two fingers into the carburetor throat of #1 and #2 cylinder carburetor cause the engine to load up with fuel.... BUT if that test on #3 carburetor causes #3 cylinder to pick up and fire, that (to me) would indicate that the #3 high speed jet is fouled. Worth looking into.

That #3 spark plug.... does it look quite dry as compared to #1 and #2 ?

The lower main bearing seal... I've never seen one so bad that it interfered with the bottom cylinder to the extent you mention (Dead Cyl).

 

[Carpfisher]

Re: 70 horse with dead hole ?

Rechecked comp.-same.
Tested coil and wire, good. Recheck for spark, good.
Looking in cylinders, top 2 wetish, plugs burned at tip from ignition (they were new), good.
Bottom cylinder, looks dry, no burned tip from ignition/combustion.-Problem.
Pulled lower carb again. Unburned, raw fuel around reeds.? WTF.
For kicks, switched carbs, top to bottom.
BINGOOOOOOOO!!!!!!!- Dead hole moves to the top.
Sooooo to rebuil or not.??
I guess I'll completely tear down and soak in carb cleaner and give it another go.
I guess I will leave the plugs in as I don't have replacements. (carb plus that is)
I am doing all this in my driveway and don't have instant access to all my tools and resources.
Just for giggles, anyone have a known good AR 434159 carb they want to sell for a fair price?
Inquiring in case a real cleaning doesn't work.
Thanks
Paul

T

 

[Joe Reeves]

Re: 70 horse with dead hole ?

The carbs aren't that complicated, actually very simple.... very unlikely that it requires replacing.

I assume you know exactly where the high speed jet is, but if not.... it is as mentioned above in the center bottom portion of the float chamber, way in back of the float chamber drain screw. If it isn't fouled and the cause of your problem, I would be very surprised.

 

[Carpfisher]

Re: 70 horse with dead hole ?

Thanks Joe, When I had the carb apart the first time I could visual and bright light that hi speed jet in back of float bowl drain screw. It was fine, same with everything I could get a visual on.
They sure are simple compared to some of the motorcycle or car carbs I've worked on in the past.
I'm back to work after 11 days off this morning, I'm a steering/suspension specialist, I have a boat "mechanic" friend who really knows a lot, (in fact he told me it was carb) that offered to go thru the carb for me (owes me some favors). Thats good cuz there gonna bury me at work, wont be able to mess with my stuff.LOL. Should have it back and on the boat for a test tomorrow night, back in the water on Sat. hopefully.
Will post some pics of the boat tonight if you'd like to see it. 20' Gregor Seahawk 4...
I upgraded the steering to No feedback 4 turn steering, installed a nice bait tank set up, redid the gunnels and cleaned up the wiring, fresh new hard wiring of the manual and auto bilge pumps, etc. I've been messing with this thing for an hour here and an hour there since ,mid sept.-did I mention I have 2 9 year old boys and an 11 year old boy ? See why I get nothing done?LOL. Plus a 14' Western with a 25 Suzuki that I redid the transom on (you should hear my spun prop story-that suzuk has a rare 6 spline prop) that I use for hoop netting-did great on lobsters this season !!!
Thanks Joe-and whereabouts are you? I grew up in Tampa (left in 76'), still have lots of Italian relatives in San Antonio. Don't like to admit it but I remember my parents dragging me and my sister to Lake Como, if you know what I mean, times were differen't then ya' know !!!

 

[Joe Reeves]

Re: 70 horse with dead hole ?

Whereabouts are you? I grew up in Tampa (left in 76'), still have lots of Italian relatives in San Antonio.

Moved from Millville, NJ in 1977 to Brandon, Fl. That brand new home fell in a hole, moved to Valrico, Fl in 1997. Sounds like your friend will have that engine running smoothly soon. I've hit those type problems in the past... can't see the forest for all the trees in front of it. I'm convinced that it's a small problem with that carburetor... does it flood up, fuel pour out of it when you pump the fuel primer bulb?

 

[Carpfisher]

Re: 70 horse with dead hole ?

No it does not, bulb gets hard and no leaks occur. From empty you can see the filter(new) and hear the fuel flowing until the bowls fill and the bulb gets hard, Haven't teated bulb check valves to make sure that they are operating as they are designed, but even if they are bad they are not he cause of current problem. Also interestingly, even though the combustion chamber was dry, the carb side of the reeds was very wet, as though there was not starvation, but lack of atomization ? Everything I can visually see is not clogged. The tube I suspect is called the "emultion " tube that runs up the middle of the larger tube to the top of the carb and another jet, which I remover and is not clogged, or another orofice concealed by a plug. Carb is soaking overnight now, will see about wire probing/air bowing the tube if I have time tomorrow cuz' my buddy flaked and I have to handle it myself, thanks for good friends. LOL.
I to am convinced it is a small problem..I'll let you know...

 

[Carpfisher]

Re: 70 horse with dead hole ?

Soooooo, carb soaked for 15 hours. Started right up and at first, as I removed power from #1 coil, it was making a difference in rpm, small but perceptible, before not perceptible at all, but kill the middle or bottom cyl. and it still almost stalls, STILL a problem with the carb.
Gonna give it to my buddy, put it back on the bottom cyl. when I get it back and see what happens. If the dead hole moves to the bottom again after James get done with the carb, I'm looking for a new, known good one....

I rigged a tube to blow thru the little tube in the middle of the larger, emulsifier tube, and it is clear.

If I decided to go deeper, i.e., remove the plugs, what's the best way to reseal them or get plugs, thanks and I'll keep you updated as to the final outcome.

 

[Joe Reeves]

Re: 70 horse with dead hole ?

Just tap the core plug with a proper size punch... that'll seal it. If in doubt, after installing it, coat it with Gasoila (red stuff).

PM sent also.

 

[Carpfisher]

Re: 70 horse with dead hole ?

So last episode, dead hole was at the top carb has been apart twice.. compared side by side to functioning carb..smoke tested idle circuit-small tube inside larger emulsion tube, smoke comes out 4 TINY hole at cut out in throttle blade and next larger, off idle port a little ways down stream. Did this on both carbs to see what was "normal' flow. Again, all jets and passage ways clear. Used a long wire peeled off a bad cable to probe, all seems good. This carb soaked for almost 2 days in an almost new 1 gal can of carb cleaner and from the get go, never had a speck of dirt in it. That's what seems so strange ?

Back together again, this time installing suspect carb at the bottom. In the process, breaking one plastic linkage retaining clip, and from manipulating the linkage rod a bit manly every time something has to be removed, carbs are not snapping back like they should be/were. which is why they show them being removed as a unit in the manual. These are all little things that I will address after figuring out the carb problem. Dead hole moves back to bottom. Not sure what's up ?

This motor is a 92 "J70TLEND". The carb is an early production unit. It has no top cover like the later ones. I haven't put a "kit" into it yet.
Needle and seat look good. Float bowl fills, doesn't leak.
New carb thru Marine Engines. Com is 165+. They # they list for this model is 434160, one number off from my AR 434159. They say 3 required. They show all carbs the same #.

I don't mind spending this money if it's going to fix the problem. It would be even better if someone had a known good carb I could use for a test. I know it's a few bucks for shipping and a bit of trust... but thought I'd ask...I guess if it works, I'd buy it if it's for sale, if not ship it back and buy a new one.

Thanks again
Carpfisher