SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: bills79southwind on August 06, 2009, 07:12:12 PM
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Hey guys,
I’ve been lurking on the site for a while and have learned quite a bit from everyone’s input. I have a 79 SouthWind with a BBC 454. I’ll post some pics later. A couple of weeks ago the boat started to run funny; primarily at 3000 rpm and up. I just noticed this past weekend that as soon as I start to come up on plane, a popping sound from the carburetor would take place. A buddy and I looked at the timing and at Idle it runs great. When the RPM’s reach 2500-3000 the timing advances like it should , but starts to bounce around and isn’t steady like it should be. :banghead: (this was done on the trailor). I’m not sure what distributor is on the boat, but it’s not an MSD. Thanks for any responses on what you think it may be.
Bill
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Welcome have you check the coil under load it will sometimes do that.
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How do you check the coil under load? I've never had to do that before
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How do you check the coil under load? I've never had to do that before
If your coil is bad are just not putting enough voltage out,so when your boats in the water or up in rpm's that would be LOAD it's not getting the voltage the motor needs causing the popping just my o2, BTW is it an internal coil ?
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It's an external coil I have Tunnel Ram as well. offenhasuer. I have no idea how to test the coil or distributor
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It's an external coil I have Tunnel Ram as well. offenhasuer.
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Your best bet would be to swap out the coil and go from their. :thumbup:
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OK.. i'll give it a start. thanks very much for the advise. I'll report back. :thumbup:
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It's an external coil I have Tunnel Ram as well. offenhasuer. I have no idea how to test the coil or distributor
Find yourself a voltmeter I believe you put it on oms see what it reads at idle then take the RPMS up an it should not drop if i remember right :banghead:
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Find yourself a voltmeter I believe you put it on oms see what it reads at idle then take the RPMS up an it should not drop if i remember right :banghead:
You can also use an old school dwell meter, you can buy a cheapie at the Kragens for like $20, they work OK...
I would say you may have a trigger problem, or a coil, the trigger BTW could be points being we don't know what you have... :thumbup:
How sure are you that it's not fuel? Sure seems to mimic a lean condition... :sly:
GT
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If you have a points distributor, check the points and condensor, too. While under the cap, check that the weight springs are where they should be.
For starters,
LO
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GT and all thanks for your responses,
I don't have a points setup at all.
I've checked under the cap and it looks perfect. I have a chrome coil by the way with no markings on it. a few of the wires attach to a square metal device that is attached to the battery side stringer. I don't have a clue what that is. I'll take some pics and post them today. Its not a fuel lean problem at all. I thought the same thing and replaced the mechanical fuel pump with a high flow holley mechanical and a even replaced my 750 holley carb with a brand new 750 mechanical double pumper marine carb and it's doing the exact same thing. Fuel pressure is great. Can I use any coil? and where should I pick one up? thanks again everyone
Bill
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Yup! Coils is coils for the most part, as long as you're using the beer can with a baby bottle nipple type. It's only when you get into the fancier Accel Supercoils or Mallory Pro-coils you CAN get into trouble using an electronic ignition and ignition box.
Any parts store should have a coil, autozone, checker..............The neighbors Suburban.............. >:D
Ray
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Thanks Ray. .I really appreciate it :thumbup:
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After doing some additional research it appears the device attached to my stringer is an ignition ballast resistor. Check that.. it's not a ballast resistor. Still not sure what it is..
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I'd be curious what kink of dist. you are working with. Does it have a vacuum advance? If so is it hooked to a vac. source, or plugged off?
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It doesn't have vacuum advance at all I'm sure of that.
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Yup! Coils is coils for the most part, as long as you're using the beer can with a baby bottle nipple type. It's only when you get into the fancier Accel Supercoils or Mallory Pro-coils you CAN get into trouble using an electronic ignition and ignition box.
Any parts store should have a coil, autozone, checker..............The neighbors Suburban.............. >:D
Ray
Ray
There are internally and externally resisted ignition coils, an internally resisted coil wont run with a ballast resistor (very well anyways).
The way to tell which you need is to turn on the ignition switch and chect the voltage on the + wire of the coil....If 12V, it is more than likeley an internal dealio ..
BTW, don't see those much.
Also bill, that box is probably a CDI box, it amplifies the signal from the distributor to the coil. Could be FOS though. :-\
GT
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the square metal devise. sounds like your terminal block.
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Ray
There are internally and externally resisted ignition coils, an internally resisted coil wont run with a ballast resistor (very well anyways).
The way to tell which you need is to turn on the ignition switch and chect the voltage on the + wire of the coil....If 12V, it is more than likeley an internal dealio ..
BTW, don't see those much.
Also bill, that box is probably a CDI box, it amplifies the signal from the distributor to the coil. Could be FOS though. :-\
GT
Haven't ever seen an internally ballasted coil on a boat at all, or in years myself. If memory serves me correctly that was a GM thing.
Hate Ballast resistors anyway, as everyone knows, which is why I run all Mallory stuff and will on the next deals as well. (Although that coil wire popping off sometimes is getting annoying! Time to make a new one methinks!)
I was thinking the same thing about the box. Does it have a chrome or anodized cover and three or four screw terminals sticking out of it? Looks like a big doorbell transformer?
Ray
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Ray,
yeah it looks like that.. I've decided to get an MDS ready to run marine billet distributor and run this since I don't have a clue why someone setup a boat with a CDI BOX. This way I will at least know what distributor I am running. It's an 83606 Billet MSD ready to run. Tired if tinkering with this darn CDI Stuff. Should be here in a couple of days. I"ll keep everyone posted.
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UPDATE: I thought I would give everyone an update of my current situation. I replaced the distributor with an MSD 83606 ready to run billet distributor and a new coil as suggested. I had the exact same symptoms. This past weekend I removed the distributor cap and took a breaker bar and turned the crankshaft damper and turned clockwise. I had some major slop in the chain (roughly 10 degrees). I took the old timing cover off and sure enough, there was some major slop in the timing chain and one tooth was broken. I ended up putting in a new manley double roller chain and gear set and just finished Monday late. A good tip to installing the timing cover back is to loosen the front bolts on the oil pan or that rubber gasket that goes on the front part of the oil pan is a major PITA. This is the only item that i didn't replace that could cause my time dilema. Sorry for the ramble. I'm going to try and set the timeing tonight and will report back. I hope this was the source of my entire problem. :banghead:
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UPDATE: I thought I would give everyone an update of my current situation. I replaced the distributor with an MSD 83606 ready to run billet distributor and a new coil as suggested. I had the exact same symptoms. This past weekend I removed the distributor cap and took a breaker bar and turned the crankshaft damper and turned clockwise. I had some major slop in the chain (roughly 10 degrees). I took the old timing cover off and sure enough, there was some major slop in the timing chain and one tooth was broken. I ended up putting in a new manley double roller chain and gear set and just finished Monday late. A good tip to installing the timing cover back is to loosen the front bolts on the oil pan or that rubber gasket that goes on the front part of the oil pan is a major PITA. This is the only item that i didn't replace that could cause my time dilema. Sorry for the ramble. I'm going to try and set the timeing tonight and will report back. I hope this was the source of my entire problem. :banghead:
Two piece aluminum Cloyes timing cover .....Just sayin :thumbup:
My gues would be she majorly jumped time which caused the broken fang...Hope all ends well...
PS............. a simple vacuum test will find this problem in a heartbeat...vacuum levels will be horrible throughout the RPM range... :thumbup:
GT
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GT,
a-MEN on the 2 piece timing cover.. Next time I'll know.
Here's my latest update. I'm totally frustrated!! :banghead: I've changed the timing chain and gears (Manley double roller) and I'm having the exact same issue. We took the dizzy cap off and rotated the harmonic balancer nut and there is no slop now in the timing chain. The timing is still jumping around when I rev the motor to around 2000-2500 RPM'S. The carb will start popping when the timing starts jumping all over. I also pressure tested each cylinder which ranges from 151-163. So here's a quick recap.
Replaced so far: MSD 83606 ready to run distributor, Accel coil, Holley 750 double pumper w/ mechanical secondaries, Holley mechanical fuel pump and Manley double roller chain and gears. The symptom has not changed at all. I also replaced the plugs and OHM'd out the plug wires which seem fine.
Any other ideas or thoughts would greatly appreciated. I honestly don't know what else to check at this point
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GT,
a-MEN on the 2 piece timing cover.. Next time I'll know.
Here's my latest update. I'm totally frustrated!! :banghead: I've changed the timing chain and gears (Manley double roller) and I'm having the exact same issue. We took the dizzy cap off and rotated the harmonic balancer nut and there is no slop now in the timing chain. The timing is still jumping around when I rev the motor to around 2000-2500 RPM'S. The carb will start popping when the timing starts jumping all over. I also pressure tested each cylinder which ranges from 151-163. So here's a quick recap.
Replaced so far: MSD 83606 ready to run distributor, Accel coil, Holley 750 double pumper w/ mechanical secondaries, Holley mechanical fuel pump and Manley double roller chain and gears. The symptom has not changed at all. I also replaced the plugs and OHM'd out the plug wires which seem fine.
Any other ideas or thoughts would greatly appreciated. I honestly don't know what else to check at this point
Here is a dumb one.................................... ..what is the voltage on the (+) side of the coil with it running? It is starting to sound like a bad ignition switch or even a failed tach... :sly:
GT
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OK, time to get back to basics with this thing. The old "Box" dealio I described I only ever saw on old Jeeps, 'tis why I asked.
Someone made this thing run with whatever was available, and apparently did so.
First, and foremost, lets get the thing timed at TDC. Forget the dampner, I think that's an issue in this case. A silver Sharpie is going to be your best friend for this.
Crank the engine over by hand (reverse, tightening the bolt) until it's #1 is at TDC on compression stroke. Use a coat hanger, works fine. Mark the dampner. Crank it over again, BBC right? at TDC and watch #4 When it starts to drop, mark the dampner again. that should be, if I remember BBC's right, 8 or 9 degrees BTDC.
Set your dizzy pointing at #1 at that point you should be able to fire it and be damn close.
I could be wrong on this thing, been many years since I did a BBC. I know it works on BBF's using #6 instead of #4, but I think I'm right. They are very similar. Enginedoctor will chime in if i'm way off on this, but I think that's where you need to go.
Ray
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I'll check the voltage while it's running tonight. I haven't done that yet.. I did connect the coil directly to the battery to take the ignition key switch out of play though. It did the same thing having the ignition connected directly to the battery.
As far as TDC I know we are right on the money there. I did the trick you mentioned when we put the new timing change and gears on. :banghead:
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New UPDATE:
I had a mechanic buddy come by and take a look at my problem. We took the valve covers off and checked the rockers and after rotating the harmonic balancer nut, we found one rocker was crazy loose. I didn't ever hear a valve tap which is odd. I ended up taking off the tunnel ram intake and sure enough, one of the exhause lifters was concaved. The cam lobe is also flat which explains a lot.
I have no clue what cam is in it so I guess I'll pull it out and get a new one and new lifters. I'm going to start a new thread to hopefully get some feedback on what to get.
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New UPDATE:
I had a mechanic buddy come by and take a look at my problem. We took the valve covers off and checked the rockers and after rotating the harmonic balancer nut, we found one rocker was crazy loose. I didn't ever hear a valve tap which is odd. I ended up taking off the tunnel ram intake and sure enough, one of the exhause lifters was concaved. The cam lobe is also flat which explains a lot.
I have no clue what cam is in it so I guess I'll pull it out and get a new one and new lifters. I'm going to start a new thread to hopefully get some feedback on what to get.
If you can swing it, go roller cam...Unfortunately there will be powdered metal literally everywhere in the motor so it should come all the way down IMHO....
Sorry to hear this, sucks for sure...
GT..
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I was afraid I would hear this... I really want to get back on the water and finish the season up since it's winding down hear on the east coast. Could I do some major damage if i through a new cam and lifter set in?
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I was afraid I would hear this... I really want to get back on the water and finish the season up since it's winding down hear on the east coast. Could I do some major damage if i through a new cam and lifter set in?
Catastrphically major I am afraid....Anyone else? :-\
GT
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UGGGGGG .. So what is involved in a complete breakdown? Sorry if that seems like a dumb question. I just don't know exactly what's involved. I'm thinking making taking it out of the boat and have a machine shop go over everything?
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Yeah, Motor comes out, tear it down, clean it thoroughly. As far as a machine shop, no if you have or have access to the correct measuring instruments for bore, main bore, cam bore, rod size and crank diameters.
Personally, I would take all of it for a hot tank and inspection. Much cheaper than buying all the tools. I have most of them, but still would ,only as a double check on myself. It doesn't cost that much.
Now, on the flip side, I have seen (DO NOT RECOMMEND) people pull the pan, pump, clean them, put it back together with no firther rip down (You're gonna have a CAM AND LIFTER INSTALL AT LEAST) Then put it together, fire it, for a few seconds, change the oils and filter, do that like 3 or 4 times, call it good and run it. And some have run for years.
Depends on whether you have the luck of the Irish or not, I guess! never trusted in that.
Ray
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We'll for now I'm throwing a new cam and lifter kit in to try and get me through at least 2 months... After the season I plan on getting it hot tanked like you suggested and go from there.. I plan on changing the oil a few times like you suggested as well. Hope this keeps me going for a 6 weeks :banghead: