1972 85HP Chrysler -- Fuel Problem??

[turtle1173]

Hi all,<br /><br /> I've been having a problem with the motor not going very fast, even with the throttle wide open (on the controls and at the tower shaft). This particular incident happened Monday. I noticed when I squeezed the fuel bulb, it was slow to fill up again. It started up however and acted fine anyway. At WOT, it takes literally 2-3 minutes to get up on plane. Even then it is not planing right. My buddy thought my prop was pitched too high.<br /><br /> After fishing, I could only go half throttle. Any more and it would start to die. At the ramp I got to messing with it and when I turned the idle mixture screw on the bottom cylinder, it had no effect. So we all concluded that it needed a good cleaning. I checked the spark and the compression, both were good.<br /><br /> I found that the bottom carb did not have a nozzle. I don't know what exactly a nozzle does but I took the carb off my 55HP and put it on this one. It is a little different on the inside but it is still a Tillotsin WB (like the others on the 85HP).<br /><br /> I took it out this evening and after I ran it at the ramp for a bit, it died. I had a terrible time getting it started again. Finally it did. It shifted fine and everything, so I went out. I could only go at a fast idle (in gear). IF I tried to go any faster, it would start to sputter.<br /><br /> Back at the ramp, it looks like all the plugs are burning. How should I proceed??<br /><br /> The line from the tank to the fuel pump is a couple years old. I checked the screen at the pump and it was fine. I replaced the fuel pump a couple months ago. If I disconnect the fuel line at the fuel pump can I check the bulb by siphoning gas into a container or is that an inadequate test? If it's a leak could it be anywhere in the fuel lines?<br /><br /> Thanks for reading my long post but I like to be thorough.<br /><br />Shane

 

[eurolarva]

Re: 1972 85HP Chrysler -- Fuel Problem??

Hey turtle1173. You mentioned when priming that it is slow to fill up. Have you tried loosening the gas cover on your tank. Might not be venting. Also you mentioned a new fuel pump. Is this a new pump or is it a replacement pump. A lot of times when you get a used pump they just take them off a motor and dont rebuild them. You may still need to change the diaphram and gasket. Does it sound like it is firing on all cylinders. The clymor manual shows how to synchronize the carbs. Not sure if this is the problem

 

[turtle1173]

Re: 1972 85HP Chrysler -- Fuel Problem??

Hi,<br /><br /> Yes the tank is properly vented and works as previously described even with the cap off.<br /><br /> I should have been more clear in talking about the fuel pump. It was the diaphram and gasket that I replaced, not the actual assembly.<br /><br /> Going by the looks of the spark plugs, it is hitting on all 3.<br /><br /> I just went outside and disconnected the fuel line at the bottom carb. When I pumped the bulb it stayed flat for a long time (a minute) before coming back full. I tried this a few times with the same result. Even then, it just sprayed a very small amount of gas.<br /><br /> I then disconnected the fuel line right before the fuel pump. The first couple of pumps seemed similar.<br /><br /> Question: How long should it take for the fuel bulb to fill back up?<br /><br /> After pumping it several times (with it disconnected before the pump) it is taking about 8-10 seconds to get firm again (which seems much better than when I first was trying it). That doesn't sound like much but when you sit there and are counting, it seems like a lot longer. Perhaps there was a partial clog that came out.<br /><br /> I checked the screen that is in the gas tank and it was clear of debris.<br /><br /> I suppose that if the 8-10 second fill up time is OK on the fuel bulb, then I should expect the same thing out of the fuel line that goes to the Carbs when I hook the line back up to the fuel pump, right? Otherwise that isolates my problem to the fuel getting through the fuel pump.<br /><br /> Is that sound logic??<br /><br />Thanks again,<br /><br />Shane

 

[turtle1173]

Re: 1972 85HP Chrysler -- Fuel Problem??

^

 

[eurolarva]

Re: 1972 85HP Chrysler -- Fuel Problem??

Have you tried putting a new primer bulb on the tank? I know you said you did it like 5 years ago but you might want to try it again. Might also want to replace the fuel line on everything and use screw type fuel hose clips on all connections including the pump to carb fuel lines(Get this fuel line from NAPA for about a buck a foot).<br /><br />Might also want to swirl the gas in your tank and dump it into another fuel can and see if you have a lot of sediment in the can. If you have no leaks on the motor it has to be somewhere from the gas can to the fuel filter.<br />Hope this helps if not it will get bumped to the top so someone else might be able to help.

 

[72INVADER90HP]

Re: 1972 85HP Chrysler -- Fuel Problem??

all so check the needle and seat in your carbs and then check the float levels you may have a needle sticking.does your your bulb get hard?<br />ALso hooke up the fuel line with the primer bulb to the top carb and pump the bulb, Does it get hard? Now hhook the line up tho the #2 carb making sure that it to is connected to the top carb or gass will shoot out and pump the primer bulb untill it gets hard. Now hook up the fuel line to all 3 carbs and sqeeze the bulb.Also make sure your float is 13/32 upside down and 1/16 with the float hanging.

 

[The Marine Doctor]

Re: 1972 85HP Chrysler -- Fuel Problem??

If the Nozzle you are refering to in the carb is the large one...that would be the high speed jet...so if you have been driving around the lake trying to go full throttle without it...that cyl gets NO fuel..and NO oil. Do a compression check of that cyl.<br /><br />TMD

 

[eurolarva]

Re: 1972 85HP Chrysler -- Fuel Problem??

Your question how fast should the primer bulb fill back up. Mine does so in about 1 to 2 seconds. I would put a new primer bulb on it. You mentioned with the gas line not connected to the fuel pump it took about 8 tp 10 seconds to re inflate. Something is wrong there.

 

[turtle1173]

Re: 1972 85HP Chrysler -- Fuel Problem??

Hi everyone,<br /><br /> I think I'm going to start by replacing the fuel line (with the bulb) and then see where I'm at. I'm going to check out my connectors also.<br /><br />MarineDoctor, the nozzle I'm referring too is the long piece that screws into the part that hangs all the way down inside the carb. The high speed jet screws into the part that hangs all the way down but the "nozzle" screws inside of this. The part I'm referring too is probably 2 inches long and a 1/4 - 1/2" in diameter.<br /><br />Thanks,<br /><br />Shane

 

[turtle1173]

Re: 1972 85HP Chrysler -- Fuel Problem??

Well, here's the latest...<br /><br /> I replaced the fuel line and bulb and it seems to be working much better. I also took the carb off of my 55HP Chrysler and put it on the bottom cylinder of this motor. I did, however, put the jet off the other carb onto this one. <br /><br /> Anyway, the end result is no difference. At the ramp, I can get close to WOT before it starts to die but it still sounds like it doesn't have any power. Same result when I took it out. I pulled the plugs and the top 2 look like they are burning fine. The bottom looks like it has excessive fuel on it.<br /><br /> I have verified the compression (138, 138, 150) and spark on all 3 cyl. The timing is dead on and I have a new set of points. That only leaves a fuel problem.<br /><br /> Should I go back to the original carb even though it doesn't have that main nozzle in it? Seems like it ran better than with this other carb. Anything else to check?<br /><br />Thanks for listening to my woes <br /><br />Shane

 

[scotiany]

Re: 1972 85HP Chrysler -- Fuel Problem??

Just for kicks, try cleaning the puddle valves . They are located on the starboard side just forward of the transfer ports. The reason I say this is that you mentioned your lower plug was oily. That's usually the puddle valve that gets plugged up.

 

[The Marine Doctor]

Re: 1972 85HP Chrysler -- Fuel Problem??

Puddle valves are for idling characteristics. Maybe the Ign coil is dying. Or the power pack is falling on its face as well.<br /><br />Maybe its not fuel related at all?<br /><br />TMD