rkclassic3 Posted May 13, 2009 Share Posted May 13, 2009 I drove 485 mile each way to buy this engine, Started it up today, and it is missing so bad, and gasoline shoots up out of the carburator, like it has a valve problem or something, so i am at a stand still now, it has excellent oil pressure 55 to 60 lbs. But a terrible miss in engine, anyone have any suggestions of what i should do next? Any help to this problem would be greatly appreciated. ARE GASKETS AND PARTS HARD TO COME BY FOR THIS PARTICULAR ENGINE? (EN402) Does it sound like i should be looking for another motor? Appreciate any input, to this matter? Was told it was a good motor and only had around 51,000 miles on it. Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/ Share on other sites More sharing options...
Rob Posted May 13, 2009 Share Posted May 13, 2009 I drove 485 mile each way to buy this engine, Started it up today, and it is missing so bad, and gasoline shoots up out of the carburator, like it has a valve problem or something, so i am at a stand still now, it has excellent oil pressure 55 to 60 lbs. But a terrible miss in engine, anyone have any suggestions of what i should do next? Any help to this problem would be greatly appreciated. ARE GASKETS AND PARTS HARD TO COME BY FOR THIS PARTICULAR ENGINE? (EN402) Does it sound like i should be looking for another motor? Appreciate any input, to this matter? Was told it was a good motor and only had around 51,000 miles on it.Verify the ignition parts are in good condition first, (plugs, wires, etc.), then run a compression check. I'll bet you have a valve stuck if the plugs/wires are good.Hard parts are a bit difficult to come by in my opinion, and I have three of those engines.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35160 Share on other sites More sharing options...
Mike Posted May 13, 2009 Share Posted May 13, 2009 It sure sounds like a stuck valve. We used to tap the valves with a rubber mallet to free them, that is also using a penetrating oil for lubrication around the stem area. Spraying your favorite lube around it can't hurt anything. May take some time, but would try that before going into the engine. Rob has the right idea of checking the compression also to tell which one is troublesome.Keep us posted!mike Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35164 Share on other sites More sharing options...
terry Posted May 13, 2009 Share Posted May 13, 2009 That is a flathead engine i beleive, and to pull the head is pretty simple, sure would tell you a little about the engine condition. Sounds like the bottom end might not be to bad. terry Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35178 Share on other sites More sharing options...
rkclassic3 Posted May 14, 2009 Author Share Posted May 14, 2009 (edited) That is a flathead engine i beleive, and to pull the head is pretty simple, sure would tell you a little about the engine condition. Sounds like the bottom end might not be to bad. terryHello:Thank you all for your input, i have 2 intake valves stuck, pulling head today, when i bought this engine it was setting out in the weather un-covered, all except a piece of plywood over engine, im sure rain water got down thru the carb...thanks everyone for your help, will keep you posted. Edited May 14, 2009 by OLD DOG Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35196 Share on other sites More sharing options...
rkclassic3 Posted May 15, 2009 Author Share Posted May 15, 2009 (edited) It sure sounds like a stuck valve. We used to tap the valves with a rubber mallet to free them, that is also using a penetrating oil for lubrication around the stem area. Spraying your favorite lube around it can't hurt anything. May take some time, but would try that before going into the engine. Rob has the right idea of checking the compression also to tell which one is troublesome.Keep us posted! Mike.Rob, And Terry.....Just as you all said ...... i took the both side valve covers off this am, and Number 3 and 4 BOTH INTAKE VALVES were stuch so hard in the block, i had to pound them down, a leather mallet, and another hammer hitting it, then prying upwards and tapping downwards with mallet, and penetrating oil...pb blaster etc...did this to both Intake Valves for 4 steady hours, then i got lucky and Located a Copper Head Gasket......everything is all cleaned up and ready to go back together tomorrow, i learned something, DONT EVER BUY A GAS ENGINE THATS BEEN SETTING OUT IN THE WEATHER UN TARPED OR UNCOVERED, as water definetly went down thru my carburator thru the manifold to the intake valve area, freezing these 2 valves into the head, will keep you all posted as how things go tomorrow.Again i thnak you all for your help and suggestions. putting another 140.00 and my time n labor, hopefully is a good fix, i am worried that number 3 will seize up again, when engines gets good and hot, thats my only worry...o well time will tell...again thanks fellows. Edited May 15, 2009 by OLD DOG Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35214 Share on other sites More sharing options...
Mark from OZ Posted May 15, 2009 Share Posted May 15, 2009 Old Dog I would pull all the valves an inspect them for pitting / rust also clean the stems and guides while you have the head off.just to be shure. may bee a quick lap. Might save another head gasket. Just a thought Mark. Quote Link to comment https://www.bigmacktrucks.com/topic/9375-en402-mack-gas-engine/#findComment-35224 Share on other sites More sharing options...
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