Update/Questions on the Boat Situation

[Hoss 350]

Many of you may remeber my previous post on my boat and how much it is sucking my will to live. Symptoms include:

Running ABSOLUTELY WONDERFULLY for about an hour (just long enough to get WAAAAY out away from the dock) and then beginning to run poorly until it finally dies. Let it sit, starts right up and runs for a while (couple minutes, tops) then does it again. Continues doing this until you let it sit for quite some time (like overnight) then it will go for an hour or so before it starts doing it again.

Always seems like it happens mostly after I put it under a real hard load (pulling a skiier, running WFO, etc.).

Anyway, I found a fuel leak, which I fixed, but no help.

I had a guy tell me that the same thing happened to his boat, and he found out that it was the resistor wire that hooked up to the coil that had gone bad. What was happening is that it got hot, stopped working, engine died, it cooled off, it got hot again, engine died... well, you get the picture.

So, I am thinking about eliminating it totally by adding a ballast resistor on a new run from the battery, and just terminating the resistor wire. I'm thinking that I can wire the new wire/resistor package up, and have it with me next time i go out, then, when it starts acting up, install my new pigtail and see if it stops acting up. If so, then VOILA, problem solved. If NOT so, then I will just insure the boat for as much as I can get out of it and light the whole cursed thing on fire. JK.

All i need to know is how to wire the new resistor, and how much resistance it will need. I have no idea about any of this. It is a GM points ignition, converted with a pertronix electronic conversion kit. The distributor is a remote coil presolite marine. The ballast resistors that I've seen look like a block with copper tines coming out of each end on one side. I'm assuming you just wire it inline in the new wire, and I also assume that the resistor tells you which direction the current needs to flow for it to work right (OR DOES THAT EVEN MATTER?) I just know so little about these old school ignition systems..... Any help would be great.

ETA - BTW, the specs call for 8-9 volts at teh coil, in case that helps you to figure out how much resistance I need...

 

[jharvey]

Hoss resistors go inline like a fuse, there's no in or out. Can't help ya with the numbers though.

You sure this thing isn't vapor locking or fuel foaming and causing this issue??

 

[Hoss 350]

You sure this thing isn't vapor locking or fuel foaming and causing this issue??

No, not sure at all. But it seems to be getting fuel when the problem happens. If I jack the accelerator pumps, I can see the fuel squirt in, but no mater how much I jack them, it seems like it never fixes the problem. So I figured if it was a fuel issue, then squirting in more fuel should have helped, but it didn't.

I think I am going to run a rubber hose from the fuel pump to the carb next, to keep it away from the hot engine and see if that helps (if the resistor thing doesn't help, that is....)

 

[Russ]

Slowly dieing, sounds like a fuel issue to me, not elec. Elec. stuff is normally on or off. I would install a fuel pressure gauge on the fuel line before adding a rubber hose to it. Find the problem first then start patching. Is the engine getting hot? Maybe a bad water pump in th elower unit not letting the engine get enough cool water.

 

[Frankenstien]

I know of some one else who had a similar problem.... Turned out his Fuel tank was not venting... eventually a Vacume would build, and the motor could no longer get fuel. let it sit for a bit would fire up ... run for a bit then die.... check your cap... Does it have a vent screw?....do you remember to open it before heading out... maybe a new cap ... one that does not vent as it should....

 

[Scooter]

Sometimes a crack int he coil will cause a similar problem. When it is cool, the coil is sealed, then as it heats up the crack expands. It will cool down a little bit and start and repeat the cycle similar to what you are having. Since it is in a pretty harsh environment it is a good possibility.

 

[bushpilot]

take a can of 'freeze' spray out w/ you...if you think its
electronic (resistor getting hot)...spray the part and run the
boat....see if you get a bit longer run time.

im w/ everyone else on this one...sounds fuel related....shouldnt
take an hour for a coil or electronic part to heat up and start
breaking down.

one of my bikes would do this...run all day long at moderate
throttle...but make a WFO run and it would die...seems the
fancy ass billet fuel filter that i installed couldnt keep the
fuel bowls full @ WOT...that said whens the last time you
changed your fuel filter ?

 

[RenoF250]

This sounds like the problem I had with my ScoutII. It made it about anhour from the house and then died. My dad was convinced it was the carburator and took it apart on the spot. Couldn't find anything so we took it home. Turned out to be a bad coil.
I really doibt the resistor is your problem, if it is dead shorted it could be overheating the coil but I don't think that is likely. I would try a new coil and check the gas tank venting, that sounds like a likely possibility as well.

 

[jopes]

my best guess's at this point are the tank not venting, loosen the cap and drive around see if that helps.

if not then check the coil out. could be it is shot. I know VW coils have the balast resistor built in the coils. typically for a points system the coil receives 6 volts or the points will melt. but since you did some upgrades in the dizzy, I have no idea what those will do. Any chance it is easy to put that back to points and see if that upgrade could be the cause?

 

[Hoss 350]

my best guess's at this point are the tank not venting, loosen the cap and drive around see if that helps.

if not then check the coil out. could be it is shot. I know VW coils have the balast resistor built in the coils. typically for a points system the coil receives 6 volts or the points will melt. but since you did some upgrades in the dizzy, I have no idea what those will do. Any chance it is easy to put that back to points and see if that upgrade could be the cause?

Okay, I'll try to respond to all advice, Thanks to all that tried to help.

Tank venting - Not the problem. Pulled the vent and blew through both ends, no problem there. Took the gas cap off last time it did it just to make sure, and it was no help.

Coil - Replaced last year trying to chase this very same problem down. So unless I got a "new" bad coil, then I am thinking that coil is eliminated.

Electronic conversion - Not the problem. It did the exact same thing before the conversion as it is doing now. It runs better when it is running with the conversion, and the conversion is designed to run a "points type" coil system, with 6-8 volts serving the coil, just like points.

Gas boiling/vapor lock - Totally possible, completely plausible. The problem seems more like fuel-related to me than electric at this point (although I change my mind from time to time...) but I've had a coil go bad on me in my old Ranger, and it acted like a fuel problem when it went, like it was running out of gas. Only, really, it was just not burning all the gas because of weak to no spark... I think the only way to check this is either a gauge inline, or to re-route using rubber. Since I already have the rubber hose I need from a previous project, I'm thinking it will only take 10 minutes to re-route next time I'm out on the water to check this theory. I wish there were inspection holes in the fuel bowl to see if it is running out of fuel or not. The only thing that makes me think that this is not the problem is that once it dies, it starts right back up. With a mechanical fuel pump, in a run-the-carb-dry situation, shouldn't it take 15 seconds of cranking or so to build up enough fuel to get the rig to start?

Fuel filter - Changed the thing three times this year alone. Not the problem. Gas in the filter is clean and water free.

Fuel tank pickup - Took it all apart and cleaned it out last fall. Not the problem.

Engine overheating - Not the problem. Gets plenty of water, and I even TOOK THE T-stat all the way out and run it without a t-stat to see if it helped. No help.

I've replaced parts to the point to where I'm down to two things left. Resistor wire feeding the coil, and fuel pump. Since mechanical pumps are either bad or they're not, i don't think fuel pump is the issue. I have a friend who referred me to a mechanic who says he is almost sure it is the resistor wire, since he has had the same thing happen to him in the past on similar boats.

The only info I couldn't get was how much resistor I need to make a pigtail for 15 cents and check the hypothesis next time it starts running crappy out on the lake.

I thought boats were supposed to be FUN....