Well, I think I solved my problem.
I pressure tested the fuel pump, had 4PSI from idle through 2.5k so I ruled that out.
I had previously tested for spark at each plug while cranking and all 4 were good, so I assumed my spark wires were good.
Finally decided to pull them all and ohm test...
Spark plugs are only a few months old.
I seem to have fixed the backfiring issue, however I'm still not getting any power. Took it to the lake today for a test run, and I can't get over 2k RPMs. Power peaks at about half throttle, and any increase just causes a deep sound from the carb with no...
Earlier today I pulled the cover and cranked the engine - all valves appear to be opening fully. Engine has hydraulic lifters & I had just reset the adjustment on those last month. No pushrods look bent. Being that it runs so strongly at half choke I’m hesitant to think it could be a valve...
Hello all,
My 1980 OMC 2.5L (120HP), Rochester 2GC carb has recently developed a backfiring issue. I was out on the lake cruising when it suddenly lost RPM and started backfiring through the carb when trying to give it throttle.
I've since replaced the distributor cap, rotor, points &...
Replaced ball gears, impeller and shaft. Reshimmed everything in the whole outdrive. Had everything completely torn apart and now going back together, hoping to go for a test run tomorrow. Shift cable is in good shape thankfully. Definitely kicking myself for spending as much as I have on this...
I’m in Oregon.
Looks like the previous “mechanic” had replaced the shims behind the rear bearing race with a crudely cut piece of copper or brass, was pretty bad. I can’t find the specialty shim tool anywhere (908573), not sure how I’m going to figure out new shims for the new bearing.
Well, I also just discovered I think I was on the right track with some hack changing the bearing. The inner race of that bearing is also cracked. Upon tapping it off, the mounting surface of the ball gear shaft is totally screwed up, lots of ridges from however they pulled that bearing off...
Hey all,
I'm working on rebuilding the upper gearcase on my 1980 OMC 400 stringer drive. When attempting to shim the ball gear shaft, I found out that the bearing race for the opposite end of the ball gear shaft, deep in the housing, has spun in its place. I was able to pull the race out by...
Finally got my engine reinstalled after replacing my stringers, deck and motor mount beds. I did my best to make sure the mounts were all at the same height as previously, but in case of any error I'm trying to figure out how this front motor mount is supposed to be setup. It's a manual trim...
I'll take a look at that distributor shaft. I took a look at the counterweights etc already, everything seemed in order there.
I don't think it's really a miss - it sounds more like a burble from being too rich. I've tuned plenty of motorcycle carbs, but those are easy - just move a clip on the...
Found source of leaking rear main seal - crankshaft had a bit of rust on the sealing surface. Cleaned the shaft up and put in a new seal, no more leaks! Also took the opportunity to clean out the oil pan - had about an inch of standing miky oil that couldn't be pumped out through the drain tube...
Took off the flywheel cover to get a better look at the oil coming out. Not as milky as I thought, caught some on paper and its the same color as what's in the pan (still has a tiiiiiny bit of white color to it, I've changed the oil twice but can't pump out the last little bit in the bottom of...
Now I'm just confused by that rear main seal leak.
Ran the engine again for ~20 minutes. Rear main is literally pissing oil. Weird thing is...the oil dripping from the bell housing is very milky, but the oil on the dipstick is still clean. Is there some sort of water passage near the rear main...
I have good news!
Got the engine in the driveway, ran it for 5-10 minutes hooked up to water. So far so good! Ran decent considering there was no carb gasket, and no signs of water or fuel in oil! Got the temp up to about 130 or so, but it started snowing pretty good and I wanted to get...
Well, I got the heads and block all cleaned up and back together. Threw the old manifold on for a test run (planning on replacing it, just want to confirm engine is good before shelling out $300). Ran the engine for about a minute with no water to rule out the fuel system - oil still looks...
