ezgo cart with robin EH35C not revving up

[borntorun]

Late 1990's vintage .. carb was clean even before going thru it. all ports, passages, and jets were flushed and blown out anyway, all jets were removed and found open and clean. after reassembly, carb spray was forced through all ports and passages and everything checked out...

all intake gaskets replaced , fuel pump working as it should and clean new gas new filter .... carb bowl is getting adequate fuel, float and vents working properly... throttle body and choke working properly, linkages providing full-open to full-closed as it should...

before and after carb work, motor still doesn't get up to speed. doesn't make any difference if choke is varied in positions between closed to full open, nothing helps.... there is a great deal of carb backspray out the throat while engine runs, if carb baffle is not in place.

When baffle is removed, engine gets up to speed enuf that belt moves into highest speed position on pulleys (tranny in neutral) , however it takes almost ten seconds for this. ... When baffle is installed, engine does not produce enough rpm to move cart beyond a walk... Acts as if baffle is creating air restriction, and keep in mind these tests were done with air cleaner assy removed... Installing air cleaner assy does not make symptoms worse nor better (no change) ..

air cooling fan and fins were blown out, there was mouse nest debris. although engine seems to be getting enough cooling air, when it gets hot engine dies and will not restart, however will backfire and sputter sporadically while cranking, no matter choke position. Oil is fresh and spark is plenty hot at plugs.

Except when it heats up and dies, engine runs well even when not developing enough rpm to do more than crawl. Thought about governor sticking but the throttle butterfly is wide open throughout this test with no difference. Any ideas?

[Larry1950]

I recently has a similar problem with a EH29 (same motor only smaller displacement) Found the inner intake gasket missing, plus the cam timing was way off. IF the cam timing is off too much it can bend the valves. The intake baffles and air filter must be in place for proper intake restriction. Also check for a plugged exhaust, if mice got in the muffler the motor can't breath. It sounds to me like restricted exhaust, unbolt the muffler and see what happens. Check the valve clearance by removing the valve cover and set the valves to .004" being sure each cylinder is tdc and the cam is timed. It is possible the valves are out of adjustment.

[borntorun]

thanks larry, the mouse/muffler issue crossed my mind but I dismissed it because the pipe is so tiny. ... I suppose they could've gotten in there, they say mice can distort themselves and go places we'd never believe....
Brainflash, maybe even old bee nests in there.. It had been stored outside.

Funny the symptoms didn't click for me because I had a mice/muffler problem on an old VW rabbit convertible awhile back and didn't know it... floor it and it wouldn't get past 1900rpm. It had been parked a couple years and when it was awakened the owner said it acted constipated, wouldn't stay running and overheated at an idle. While I was letting it run at 1800rpm for a few minutes while checking things over such as water circulation and fuel mixture and timing, all of a sudden a ton of the worst-smelling smoke started to appear and then I knew what it was. I floored it and "POW!" several burning wads of nest crap blew out the back end. The car ran like a jackrabbit after that. Haha maybe you're right. How soon I forget. Person I bought ez-go from said it ran great before it sat a few years. Will check timing and valve lash too just to be thorough (both were on my last-resort list). thanks again

[Larry1950]

Your welcome,hope it works out. I just got my old 10hp outboard out for the first time in 3 years at my cabin. It started OK but wouldn't rev, ( yes I drained the carb when put away) all of a sudden this huge bubble of mouse nest and a couple of dead mice came floating up from the underwater exhaust. Runs great now

[borntorun]

you inhumane mouse killer loL

[borntorun]

Good to hear you keep carbs drained.. with todays crappola "gas", I drain tanks, run carbs dry, and drain fuel pumps on anything that's going to sit more than a month. The stuff raised real havoc with all our old trucks and tractors, and we finally accepted the fact "gas" isn't going to ever be what it was before. We had to find ways to deal with the crap we're stuck with, and draining seems to help a lot as long as we're diligent. On the ez-go, although carb was very clean (apparently drained), the fuel pump was full of the typical dry gummy fish eggs I find with ethanol-laced fuel. Took it apart and cleaned it out, luckily the pump works again.

[Larry1950]

I make a lot of money each year from those who leave gas in the carbs and fuel pumps. Everything from lawnmowers to boats, kinda the neighborhood fix it guy. Good thing I am retired. I buy gas engine powered stuff at garage sales that don't run or run on choke only for little of nothing, clean the carbs and resell them for good money. I just bought a 6500w generator that wouldn't start (2 years old) for$35.00, cleaned to carb out and resold it for $350.00. Not bad for less than an hours work. Got lotsa stories about how it ran fine when it was put away, and it couldn't be old gas in the carb (GOO) Also have run into my share of plugged exhausts and oddball stuff.

[borntorun]

done same, lotsa people just don't get it... they look at you as if you have three heads when you suggest they drain their things...

I found what the engine's problem was... after determining the muffler was not plugged, I popped the plugs and valve cover and timing belt cover. The valve adj was right on. So I stuffed a screwdriver in sparkplug hole to gauge when I got TDC (by hand), but while turning I noticed the exhaust valve closed about two inches BTDC (in relation to screwdriver travel). I thought that was odd and continued to turn motor and monitor all valve's action in relation to piston travel. Sure enough, the cam seemed to be a tooth advanced. Valves were operating too early. I put it back a tooth and now it runs quite well and no carb blowback. Early closure of the exhaust valves caused compression to build at the end of the exhaust stroke, and the blowback happened when the trapped compression was released as the intake valves opened. Anyway, the timing belt was not original as it didn't have the ez-go numbers on it. Somebody changed the belt at some point and it is worn. They either didn't get it timed right or it jumped a tooth. I have the correct numbers for the belt and will be changing it out soon. For now it runs great.

[Mimer020610]

I am having kinda the same issue my will run but when I get to a hill all it does is bog down, I was thinking the timing off or not getting enough gas please help me

[Larry1950]

Glad you found the problem, your lucky being advanced it didn't bend a valve. I had the same problem on the one I worked on only it was retarded by 4 teeth using the screwdriver tdc method. Maybe this will help engine diagram and cam timing marks http://www.golfcartsforum.com/golf-c...-diagrams.html