Took a CHANCE, Bought a 7234/Excessive Smoke/no power

F100Panel · May 30, 2010

Saw this 7234 4x4 with Loader on E-Bay. Bought it for what I'd guess the loader would go for ( IF some one actually needed a loader..other than that the loader ain't much..

) Problem that has to be dealt with once delivered- Excessive smoke and lacks power. Starts OK/loader & power steering work OK, no noises reported and the 3 point hitch don't lift/I have no use for that anyway....... Nothing else known about the tractor... I'm hoping I find a mouse nest in the air intake or muffler but likely it will need an engine..especially after reading some posts here about Cub Cadets... If I had read them first I probably wouldn't have bought the tractor-I thought Mitsubishi made good stuff? BUT, I've managed to find an owners manual on line but not a service manual on line that has service info for the engine. Anyone have a link for the engine service or tractor service and repair in general that includes the engine? With that any Cub guys out there that may have seen this before & and have some ideas of what I should look at off the top of their head? Is the pump for the 3 point lift & Loader/power steering Hydaulics one and the same? It would be nice if the 3 point hitch pump was different & causing the engine to be under load all the time but at this point I'm just fishing for things to look at when it arrives and fully prepared that it may need an engine....

OldMachinist · May 30, 2010

Here's a link to where I uploaded the service manual. Cub_Cadet_7000_Series_Compact_Service_Repair_Manual.pdf
Hope it's something simple.

F100Panel · May 30, 2010

THANK YOU!!! For the Manual Old Machinist.. I always thought Cub Cadet was a well made line of Tractors.. The more I read MTD seems to have taken them over? If thats the case then I expect junk much the same way MTD ruined the Troy Built line.. I'm from the Troy NY area.. Gardenway going under was a SAD thing to see....Then even worse the Troy Built name start appearing on pieces of tin tractors at the box stores.... Though there still appears to be a Cub Cadet fan base here on TBN...

I'm still trolling for ideas though from anybody who may have seen this before/excessive smoke & lack of power..

Brad_Blazer · May 30, 2010

If you can rebuild with new pistons, sleeves, and bearings the engine should run like new.

OldMachinist · May 30, 2010

You didn't say what color smoke.

Black smoke is usually a signal that there's too much fuel, not enough air or injector pump timing is off. One of the most common causes of this condition is an air inlet restriction. The cause may be a dirty air filter, a collapsed intake hose or even an exhaust restriction.

White smoke usually occurs when there is not enough heat to burn the fuel. The unburned fuel particles go out the tailpipe and typically produce a rich fuel smell. It's not unusual to see white smoke in the exhaust during cold weather until the engine warms up.
Bad glow plugs or a faulty glow plug control module can cause white smoke on engine start up. Low engine cranking speed may also produce white smoke.
If white smoke is still visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timing or a worn injection pump. Low compression can also be a source of white smoke. Air in the fuel system can also cause white smoke.

F100Panel · May 30, 2010

Old Machinist- Black smoke all the time... I'm thinking air restriction either exhaust or intake, bad injectors letting in too much fuel? or Timing off.. If there was not enough compression, white or blue smoke all the time? Any of my ideas have merrit in your mind? Or any more you may have?

OldMachinist · May 30, 2010

That's where I'd start. Could just be a clogged air filter or rodent nest like you said. Then I'd have a diesel shop test the injectors. Next would be the pump timing. Pump timing is controlled by adding or subtracting shims where it mounts and is covered in the service manual.

F100Panel · May 30, 2010

Thank YOU!!! Old Machinist.. A second opinion is always good for pumping up the ambition to get'er done...

Kernopelli · May 30, 2010

I have never owned a cub but have owned six or seven 3 and 4 cylinder Mitsubishi tractors and have been impressed with every one of them. I currently have about 1400+ trouble free hrs on a 24 hp 3 cylinder Mits and it still runs like the day I got it 7 yrs/1000 hrs ago. I think the others are right on track about it either being an air or fuel issue. You mention that the black smoke is constant and assume that this means even while sitting at idle as well ( i.e. tractor not in gear and putting a load on the engine) but if not, I also want to throw out the possibility that it is simply something that is putting a constant load on the engine, like stuck brakes or even (maybe) a frozen bearing, etc in the drive train???

As far as the 3 point hitch, I'm curious why you don't need it? One thing you may not have considered is that if you are going to be using the loader much you will definitely want the 3 point to attach some counter weight to. It may be a simple fix, I have been down that road on several occasions. Assuming the loader works then it's not a pump issue so it could be a lost pin in the linkage ( first place to check), a worn seal on the lift cylinder or trash stuck in the relief valve or control valve. The last three require a little more disassembly but certainly doable with a manual and basic tools/ mechanical ability. Good luck and keep us posted on what you find.

On edit: I looked at what I assume was the auction ( http://cgi.ebay.com/1997-Cub-cadet-...?cmd=ViewItem&pt=Tractors&hash=item2ead3da722 ) and I'd say you got a good deal. I don't think you you have a major issue at hand. Even if it is new injectors or an injector pump rebuild you are probably only looking at $300-$400 for the latter. I don't have a stitch of faith in MTD but Mitsubishi makes solid tractors and I seriously doubt you have serious problems based on the black smoke. When you say "lacks power", how bad is it?

Sub-Cadet68 · May 31, 2010

Ok, I'm gonna throw this out there.
I have a 5264D. 3 cyl daihatsu diesel.
My 3point control does NOT pop back to neutral once it reaches the top of it's travel. Hence, when the mower deck, rake, weight box etc... Get to the highest point, I HAVE to center the lift lever or my tractor has NO power & I can hear the pto pump straining.
If your 3point isn't responding at all I'd check for a bent/broken linkage holding the valve open.
Good luck!

F100Panel · May 31, 2010

I LOVE this site. Just as I'd hoped, people who have been around Cub Cadets are throwing out ideas.. PERFECT.... I've yet to investigate any on the list as the tractor has not been delivered yet...
Kernopelli- Yes, thats the E-Bay tractor.. I have a Commercial mower, 6 way blade dozer & 10 ton 4x4 backhoe and a Cushman Turf Truckster with Hi/Low range/meant to be off road, PTO & implement hitch that we only use for the hyraulic up/down dump box on it. I can't think of anything I'd need the 3 point hitch for... I bought the tractor for the wife actually to move her landscaping stuff around with- mulch & clean up & the like... tulip picking duty if you will.... If I stumble across a 6 foot hoe I'd likey pick it up & put it on the tractor...for tulip picking.....

SubCadet 68- Does your machine have power steering? If so when your three point hitch is overstroking does the power steering still work? I was wondering in the original post if the pump for the 3 point and the power steering/loader were different & maybe the 3 point pump/3 point issue was lugging down the engine....

wdchyd · May 31, 2010

F100,

Not being a dieselpro I'd like to throw in my 2cents....my experience on previous diesels I've owned, if you're gonna do any major repairs then start with injector pump and injectors.(you'll end up doing them anyways if there is major engine work to be done)....personally 4 times this has cured smoking and power troubles for me on different equipment, although others here can better hone in on your problem....

Sub-Cadet68 · Jun 1, 2010

F100Panel said:
I LOVE this site. Just as I'd hoped, people who have been around Cub Cadets are throwing out ideas.. PERFECT.... I've yet to investigate any on the list as the tractor has not been delivered yet...
Kernopelli- Yes, thats the E-Bay tractor.. I have a Commercial mower, 6 way blade dozer & 10 ton 4x4 backhoe and a Cushman Turf Truckster with Hi/Low range/meant to be off road, PTO & implement hitch that we only use for the hyraulic up/down dump box on it. I can't think of anything I'd need the 3 point hitch for... I bought the tractor for the wife actually to move her landscaping stuff around with- mulch & clean up & the like... tulip picking duty if you will.... If I stumble across a 6 foot hoe I'd likey pick it up & put it on the tractor...for tulip picking.....

SubCadet 68- Does your machine have power steering? If so when your three point hitch is overstroking does the power steering still work? I was wondering in the original post if the pump for the 3 point and the power steering/loader were different & maybe the 3 point pump/3 point issue was lugging down the engine....

It does have power steering. But it still works fine when the 3point is locked in the raise position. Just a bit sluggish.
I read the eBay ad on your machine. It seems pretty clear in the description that the rig has a known engine problem. I hope it works out for you

F100Panel · Jun 3, 2010

Just as an update... The tractor has sat for a long time. I had it running last night. Initially lots of blue/black smoke with pup pup pup pup sounds comming out the exhaust with the diesel knock of the next cylinder overworking. Then it all cleard up for a few minutes/sounded right & smoke stopped then it starterd again. The first thing I'm going to do is have the injectors done. When starting I've also noticed you have to be very careful about having minimal throttle or the engine loads up FAST. I believe that to be another pointer to the injectors...
The power steering works fine but the loader very slow. I believe at initial look power steering, 3 point & loader all run from one pump? I'm thinking something is amiss in the 3 point control valve but my first thing is to get her running consistently good. With the pup pup pup sound & excessive smoke comming and going I don't think at this point the engine is bad/possibly sticking valve or rings but the plan is or should be to verify the injectors are in working order first?

F100Panel · Jun 5, 2010

I think I may have found the problem but I hope that the problem has't caused damage... Working on the engine today, I note Orange RTV EVERYWHERE... This engine has been totally apart... The third injector in line was not even finger tightened down... That would account for the skip... The tractor was said to have sat for a long time then auctioned.. I'm wondering if the engine was rebuilt & had the no pwer & smoke issue from the get go & put to the side.. Everything is clean around the engine, even hard to reach places.. I'm taking the injectors down to have them tested & I'll put'em back & try again... Now I'm concerned about that cylinder with the loose injector has damage from the unburned fuel building up... I'll keep you all posted....but then again I had said from the beginning I was prepared to put a motor in it..

While here I did figure out that there are two pumps on the left side of the machine coupled together. Rear pump for power steering and front for the loader/3 point hitch. Once running again I'll have to have that front pump tested. If it ain't that Im curious about the manifold block for the loader if the connections there are correct. Anybody have a 7234 with a Cub Cadet 476 Loader I could send a picture to to see if the connections look to be in the right ports? Do these manifold blocks ever go bad?

OldMachinist · Jun 5, 2010

It sounds like the person that worked on it didn't know what they were doing. They probably didn't know about timing the pump so it痴 highly likely that the injector pump timing is off.

Kernopelli · Jun 5, 2010

Did you try tightening the injector then running the engine? Just curious if that could remedy be the problem...this may not be the only issue but could account for low compression and unburned fuel/loading up/excessive smoke.

The first things to check concerning the slow loader are:

Hydraulic fluid level.

Quick connects...if the loader has them, make sure they are securely seated. Take them off and recouple them.They often appear to be properly coupled but can cause a number of issues when not.

Check the the filter and screen on the hydraulic system. If either one are partially clogged it will slow the hydraulics down.

If it's not any of these, get a 3000psi gauge (about $15) and plumb it into the end of one of the hydraulic hoses going to one of the cylinder and then cycle that function. I would speculate that the pressure should be somewhere around 2000psi +/-. If the pressure is in the ball park then it's time to start looking at other things...cross that road when it comes.

F100Panel · Jun 7, 2010

Update- With the injectors out rather than tighten that one loose one I figured I'd just get'em tested... Kinda like spark plugs, you start there..

& I'm a little lazy in my old age...

I have had issues with Qwik connects in the past... I hit a curb with my plow truck & the snow plow stopped turning.. drove me crazy.. Turned out I damaged a Qwik Connect. I plan now to eliinate the loader from the circuit & qwik connect the pump to the 3 point direct & see what happens after I get her running again..

THANK YOU ALL FOR ALL THE IDEAS!!!!!

Brad_Blazer · Jun 7, 2010

If you put a pressure gauge between the hyd. pump outlet and the first valve it will display the working pressure all the time for every circuit and putting it there is probably much easier than bypassing the loader especially whan you consider the pain of an inoperable loader. Pressure should be close to zero when not operating the hydraulics.

You will think of uses for the 3ph.

F100Panel · Jun 10, 2010

Update- Ok..... Diesel Shop said 2 injectors would be questionable to call questionable & one injector totally shot. Had them rebuilt. Put'em in & bled'em & then started the tractor.. All kindsa smoke & noise then she settled down & smoke cleared. While running I bled the injectors again/heard a distinct difference that was the same for all three cylinders while I had the injector nut cracked. Runs clear, idles good.. Now for power.. My driveway is a long decent grade. Had a new 28HP tractor here before about the same size & weight. Could not climb my driveway in highest gear with the 28HP tractor. This Cub almost makes it in highest gear/barey noticable smoke while bogging down... OK the power is OK.. I bring it up to the garage & shut it off, tinker around about 4 minutes & start her again.. Not the fastest starting, turned over likely 3-4 seconds which is a bit much for a warm diesel & started REAL Smoky, cleared in a few seconds. I don't know how old the diesel in the tank is/that may be a factor... Smoke was brown BUT......DID I SMELL A HINT OF STEAM in that smoke? Before I start her again I'll disconnect the fuel supply line from the injector pump & turn the key on & let her pump herself out & then try agin with fresh fuel.... Now I'm thinking....head gasket maybe/hopefully not a crack somewhere.....