I would appreciate any help or suggestions from the group.
Here's a list of symptoms: 1. Hard to start when cold. 2. Starting with throttle unlocked, the throttle seems "unbalanced", that is there is very little difference in the throttle position where the engine will just barely run without dieing and where it is over-revving. 3. Idle is rough, seems like one or more cylinders are missing. 4. After a cold start, I can run out from the dock at about 1500 rpm. It will be rough, but it will run. After a run of a few minutes, if I give it throttle it will take it and get up on plane. At speed the engine runs great, but after I run it a while and it warms up good, when I come back down to idle it will die. 5. At this point, I have to release the throttle to start it and it only wants to run above 2000 rpm. If I can get back to neutral without it dieing, when I put it in gear and try to give it throttle, it dies, but if I go quickly from idle at 2000 or so rpm and slam it back to idle and into gear, it will take the throttle.
Here is what I have done:
1. Adjusted all the linkage adjustments, timing, pickup, synchronization, etc.
2. Replaced plugs
3. Disassembled and cleaned fuel filter and carbs. They had some grit and an tar-like residue in them. I was unable to get the pilot jets and pilot air jets out. They had been screwed in so tight (or corroded) that the screwdriver was cracking the bronze screwdriver slot, so I gave up. But I soaked all metal parts in carburetor cleaner and rinsed with water and blew out with air. After this cleaning, the engine started (cold) and idled smoothly and I adjusted the idle speed. I congratulated myself on a good repair and put everything back together. At the dock the engine took throttle smoothly up to 2500 rpm in gear with no problems.
Two weeks later I took the boat out and it was pretty much business as usual. It started easier than usual, but wouldn't smooth out. I ran out from the dock and gave it throttle and it came up on plane just fine. Ran good with a couple bursts to full throttle. When I pulled back on the throttle to come back into the channel, it died. Started OK, except that, even though it was warm I had to choke it. Finally figured out the slamming into gear thing so I avoided having to swim to shore.
I have very few additional ideas -
1. Pull the carbs and look for the tarry residue. If there again after recent cleaning, maybe a problem in the oil injection tank or hoses.
2. Pull the carbs and get the pilot jets out (with ez-outs if necessary and replace with new) and be sure that all junk is out of the carburetors.
3. Try adjusting the pilot needles to get it to smooth out. I have the service manual and I can't find any procedure for adjusting them except to screw them in and back them out 5/8 turn.
Anyone got any ideas about what is going on with this engine?
Thanks,
Al
Here's a list of symptoms: 1. Hard to start when cold. 2. Starting with throttle unlocked, the throttle seems "unbalanced", that is there is very little difference in the throttle position where the engine will just barely run without dieing and where it is over-revving. 3. Idle is rough, seems like one or more cylinders are missing. 4. After a cold start, I can run out from the dock at about 1500 rpm. It will be rough, but it will run. After a run of a few minutes, if I give it throttle it will take it and get up on plane. At speed the engine runs great, but after I run it a while and it warms up good, when I come back down to idle it will die. 5. At this point, I have to release the throttle to start it and it only wants to run above 2000 rpm. If I can get back to neutral without it dieing, when I put it in gear and try to give it throttle, it dies, but if I go quickly from idle at 2000 or so rpm and slam it back to idle and into gear, it will take the throttle.
Here is what I have done:
1. Adjusted all the linkage adjustments, timing, pickup, synchronization, etc.
2. Replaced plugs
3. Disassembled and cleaned fuel filter and carbs. They had some grit and an tar-like residue in them. I was unable to get the pilot jets and pilot air jets out. They had been screwed in so tight (or corroded) that the screwdriver was cracking the bronze screwdriver slot, so I gave up. But I soaked all metal parts in carburetor cleaner and rinsed with water and blew out with air. After this cleaning, the engine started (cold) and idled smoothly and I adjusted the idle speed. I congratulated myself on a good repair and put everything back together. At the dock the engine took throttle smoothly up to 2500 rpm in gear with no problems.
Two weeks later I took the boat out and it was pretty much business as usual. It started easier than usual, but wouldn't smooth out. I ran out from the dock and gave it throttle and it came up on plane just fine. Ran good with a couple bursts to full throttle. When I pulled back on the throttle to come back into the channel, it died. Started OK, except that, even though it was warm I had to choke it. Finally figured out the slamming into gear thing so I avoided having to swim to shore.
I have very few additional ideas -
1. Pull the carbs and look for the tarry residue. If there again after recent cleaning, maybe a problem in the oil injection tank or hoses.
2. Pull the carbs and get the pilot jets out (with ez-outs if necessary and replace with new) and be sure that all junk is out of the carburetors.
3. Try adjusting the pilot needles to get it to smooth out. I have the service manual and I can't find any procedure for adjusting them except to screw them in and back them out 5/8 turn.
Anyone got any ideas about what is going on with this engine?
Thanks,
Al