295cc Problems

savvfj

Newbie here, great site, lots of info. Have a '94 TXT with 295cc Robin. Purchased last year and went through the much needed maintenance myself (plugs, air filter, all belts (including timing), both clutches, engine and differential fluid, gov assembly, etc.). In good shape overall, but cart used oil based on the smoke from the exhaust, but didn't think it was too bad; I was wrong Loud noise came from cart at high rpm recently, also realized oil was very low. Took me a while to diagnose, but found that one cylinder has 0 compression, the other cylinder is normal. Short version is I believe the connecting rod came apart. Piston in said cylinder appears to be sealed tight still. Figure the motor has to come out, but worried about potential damage to crankshaft or cylinder wall, or worse something else Any guidelines or things to consider when beginning this job would be appreciated. If crank is damaged can you turn it or do you have to get another one? Is it possible to leave the piston in the cylinder and attach a new connecting rod?

BGW

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rusty shackel

take off valve cover and make sure intake valve did wear up it the head.

rusty s

ez go go

If that one piston is not moving with the other one, you have major issues. More than likely with a low oil condition, you broke a rod cap. It's a toss up on whether or not you damaged the crank. Take it out and break it down. These cranks can't be turned and they aren't cheap. On the piston, you said it was smoking anyway so if the crank is useable you might as well do a rebuild while it's out especially while your that deep in the engine. Good Luck

savvfj

Thanks much for the info. Guess I'll know more once the motor is out and I tear it down. May consider trading for another 295cc if anyone has a rebuilt or new one available since I'm not sure if I have the setup to complete this project myself.

ez go go

Check the for sale section... I saw a 295 earlier this week. Good Luck..

savvfj

Okay, have an update. Motor is out a I've gone through it. One of the rods came apart and was in multiple pieces. Broke the skirting off the associated piston as well. Didn't not damage cylinder wall however (can still see the cross-hatch). Have ordered 2 rods, 1 complete piston, gasket and seal set. Have 2 questions: 1) The crank journal for the broken rod had alot of aluminum on it. Have gone through the muratic acid/emory cloth process briefly and gotten 95% of the aluminum off of it. Looks to be in good shape, but how do I know for sure that the crank is suitable for reuse? Was told I can take the old rod from the non-damaged cylinder, attach to the crank journal I am cleaning and rotate it around to "feel" for any clues that the crank journal may be damaged beyond reuse. Any thoughts on this? I'd hate to rebuild the motor with the same crank only to find the crank needed replacement. 2) See attached pic. Note the 2 "vacuum" lines coming off carb. These weren't connected to anything, just dangling loose. Haven't found any diagrams that show if/where these need to be connected, and there are no vacuum ports on the motor that don't have lines connected to them. Surely these carb vacuum lines aren't meant to hang loose? Was thinking of "T-ing" the 2 vacuum lines together and routing them to the back of the air intake box. Any need to do this?

Attached Images

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Doc's BoneCracker

Mine had them as well I never did figure it out but I did t them like you ask about and it seemed to do fine. that was last summer and no problems yet.

ez go go

No connection on the lines.... I think they are overflow lines if the carb. float sticks. They are dangling down to keep trash out of them. As far as the crank, keep working with the acid and cloth... LIGHTLY...

savvfj

When I broke this motor down I found that a rod cap had apparently seized on the crank journal, broken/come apart and broken the skirt of the associated piston. For the rebuilding, I replace both piston rods, 1 piston, 1 oil ring and 1 compression ring along with a seal and gasket kit. I purchased a digital micrometer and checked all components being resued to make sure they were within spec'd tolerance. The crank journal on the rod that came apart was coated with aluminum from the rod. Muratic acid removed 95% of the aluminum. I couldn't find fine enough emory cloth locally to remove the rest, so I used in sequence 400 grit-800grit-1200grit sand paper LIGHTLY, which polished the crank journal to a mirror finish, checked the crank journal with the micrometer and it was within spec. I did not have to replace any components of the head. I did remove all valve assemblies and clean them up, making sure to put them back as they came off. Carb was good working order before as well, so I simply cleaned out all ports and float bowl with carb/choke cleaner. Reassembled all components making sure to tighten to torque spec. Both cylinders are now reading at 160psi compression, and the motor is very strong after the first test drive!!!! Couple other things I learned FYI:
1) Valve adjustment - this motor likes the clearance EXACTLY at .004. .005 clearance of the valves made the motor backfire slightly at first test and tune.
2) The 2 conspicuous "vacuum" lines dangling free of the carb DO NOT LIKE TO BE CONNECTED TO THE AIR INTAKE BOX. I had them routed to the box on the first test and tune, and the MOTOR WOULD SPIT/SPUTTER AND HAD NO POWER! Disconnected them, allowing them to hang free as they were proved to be the ticket for normal motor performance.

Thanks for all the input on my questions. This info, along with following the Ezgo motor guide to the "T" upon reassembly made this job go smooth for me. From now on, I'll make sure to limit my manual adjustment of the governor so I won't put undue stress on the motor by turning such high rpm's, as well as keeping an eye on the OIL LEVEL, both of which apparently contributed to my original problem!

savvfj

One final thought is that my 295cc motor does have an "oil pressure switch" installed on the fan side of the crankcase. However, this wire/connector extending from the switch was not connected to anything. I assume this connection went to an original oil warning light (not an oil pressure gauge), but I haven't found an oil warning light on my cart ('94 Ezgo). I would like to find a factory replacement oil warning light that will plug in to my oil pressure switch connection from the motor without any modifications. Any suggestions?