Disparate and out of ideas!!!!!!!!!
08-20-2003, 07:57 PM
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Disparate and out of ideas!!!!!!!!!
Ok, here I go again and I don't even know where to start. twin 454's in a 1984 36' Sonic that are either having an electrical or fuel problem of some sort the best I can guess causing intermittent partial engine power loss.
Problem: When I apply power to get up on plane, the tachs go up to about 2300 to say 2800 rpm's. The nose pitches up and then the thing won't get over to plane. If I apply more throttles, doesn't make anymore power. The boat plows along through the water. If I let it set there at that setting, eventually it "sometimes" all the sudden starts developing more rpm (I hear the engines turn up) and the boat goes on over and planes but you can tell it's sometimes still not developing the power it normally did at that throttle setting. So there we are rolling along when all the sudden the rpm's maybe jump up more and the engines are finally producing what you normally expect; she'll run about 68 mph. Your running along say at 3800 rpm, all appears normal and then all the sudden the rpm's drop off on maybe one, maybe both engines (usually one), you hear the engine(s) reduce power output. So you run along a bit longer and then all the sudden the rpm's come up again and the engine (or maybe both of them) come back up to normally expected power again. If the rpm's drop off real good, you do get some popping through the carb of the effected engine.
The problem began occurring once in awhile after I had the engines rebuilt and after spending a couple of weeks sorting out the cracked spark plug, installing new MSD 8.5 mm wires, new fuel pumps and assortment of things chasing an occasional popping I was having then at high rpm's, some of you may remember that. Once that was all resolved and I began putting a few hours on the engines (now have just under 10 hours on them) this "surging" issue began appearing and got progressively worse. It's now to the point that you really can't take the boat out unless you want to plow around in the water all day waiting for the engines to catch.
I've cleaned every electrical connection I can get to from the battery to the selector switch, starters, coils and grounds. As usual, I've been chasing the problem so long that I'm fresh out of ideas, but if I buy one more part for this thing and it doesn't fix it, my old lady is going to be over this boat thing and we all know what that means; there'll be hell to pay and I go back to the honey do's instead of my dream of 20 years or more!!!!!! So please, I sure could use some help. Thanks guys and I'm really sorry for the "novel" but I guess I'm probably approaching the end myself. I really would like to enjoy this thing after fighting it for just over a year now (always one thing or another). Never have got to enjoy it for more than an hour or so. Sure wish I could afford a brand new one. Thanks
Al
Problem: When I apply power to get up on plane, the tachs go up to about 2300 to say 2800 rpm's. The nose pitches up and then the thing won't get over to plane. If I apply more throttles, doesn't make anymore power. The boat plows along through the water. If I let it set there at that setting, eventually it "sometimes" all the sudden starts developing more rpm (I hear the engines turn up) and the boat goes on over and planes but you can tell it's sometimes still not developing the power it normally did at that throttle setting. So there we are rolling along when all the sudden the rpm's maybe jump up more and the engines are finally producing what you normally expect; she'll run about 68 mph. Your running along say at 3800 rpm, all appears normal and then all the sudden the rpm's drop off on maybe one, maybe both engines (usually one), you hear the engine(s) reduce power output. So you run along a bit longer and then all the sudden the rpm's come up again and the engine (or maybe both of them) come back up to normally expected power again. If the rpm's drop off real good, you do get some popping through the carb of the effected engine.
The problem began occurring once in awhile after I had the engines rebuilt and after spending a couple of weeks sorting out the cracked spark plug, installing new MSD 8.5 mm wires, new fuel pumps and assortment of things chasing an occasional popping I was having then at high rpm's, some of you may remember that. Once that was all resolved and I began putting a few hours on the engines (now have just under 10 hours on them) this "surging" issue began appearing and got progressively worse. It's now to the point that you really can't take the boat out unless you want to plow around in the water all day waiting for the engines to catch.
I've cleaned every electrical connection I can get to from the battery to the selector switch, starters, coils and grounds. As usual, I've been chasing the problem so long that I'm fresh out of ideas, but if I buy one more part for this thing and it doesn't fix it, my old lady is going to be over this boat thing and we all know what that means; there'll be hell to pay and I go back to the honey do's instead of my dream of 20 years or more!!!!!! So please, I sure could use some help. Thanks guys and I'm really sorry for the "novel" but I guess I'm probably approaching the end myself. I really would like to enjoy this thing after fighting it for just over a year now (always one thing or another). Never have got to enjoy it for more than an hour or so. Sure wish I could afford a brand new one. Thanks
Al
08-20-2003, 08:01 PM
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It may be that one of the engines has sticking advance weights in the distributor. If one engine is lagging,the other one will not pull the boat over onto plane. Once it breaks over it uses less power so you can run,but this would also explain the "catching up" after a while. Check it with a timing light on both engines.
08-20-2003, 08:08 PM
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have you checked your fuel lines/filters/ separators for blockage? try installing a mechanical fuel pressure guage on the carb to see if you are getting adequate fuel pressure to the carbs.
08-20-2003, 08:28 PM
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Originally posted by insptech
It may be that one of the engines has sticking advance weights in the distributor. If one engine is lagging,the other one will not pull the boat over onto plane. Once it breaks over it uses less power so you can run,but this would also explain the "catching up" after a while. Check it with a timing light on both engines.
It may be that one of the engines has sticking advance weights in the distributor. If one engine is lagging,the other one will not pull the boat over onto plane. Once it breaks over it uses less power so you can run,but this would also explain the "catching up" after a while. Check it with a timing light on both engines.
Al
08-20-2003, 08:35 PM
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Originally posted by THRILLSEEKER
have you checked your fuel lines/filters/ separators for blockage? try installing a mechanical fuel pressure guage on the carb to see if you are getting adequate fuel pressure to the carbs.
have you checked your fuel lines/filters/ separators for blockage? try installing a mechanical fuel pressure guage on the carb to see if you are getting adequate fuel pressure to the carbs.
Al
08-20-2003, 08:41 PM
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Originally posted by formula31
Get fuel pressure gauges on both engines and sit someone back there to watch them while any of this is going on.
Get fuel pressure gauges on both engines and sit someone back there to watch them while any of this is going on.
Al
08-20-2003, 09:13 PM
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I had simular problems with my boat earlier this summer....fuel filters had some watery crap in them....replaced the filters but still had problems..pulled the carbs apart and found water and more crap in one of them. I rebuilt the carbs, replaced the filters again, but before cranking the engines, I pulled the fuel tank sending unit out and used a hand pump to remove the remaining water and crap from the bottom. I got about a cup of it out of a 140 gal tank. Put it back together and have had no problems since. Maybe you have the same problem.
