Chevy 350 (jet boat) wont start

[Chad D]

hey I know that most of you aren't jet boat guys but the engines should be simmilar especialy with just getting them to start. I have an 84 cimmaron 18-ss with a 350 and a berkley 12jf jet drive. about 4 weeks ago we were on the water and something happend and started blowing fuses. hotwired the boat and got is close to the ramp and it loaded up like it was flooding and died at ramp. no big deal put it on the trailer left it be for a few weeks as i was out of town I have since gotten the wireing figured out and fixed. the previous owner was overloading circuts so I spread the load out and thats all fine. Im trying to get the boat to start so I can see why it was loading up and it wont enven try to fire. I checked the coil it has power when the key is in the on possition, and there is power going to the points and they are gaped at
.022 like malory says they should. (i have a mallory 670 distributor) the engine will just turn over with out even poping off on one cylinder. don't know where to go from here. btw the cap rotor and all that stuff is fine it has bearly been used this year.

 

[Don S]

Re: Chevy 350 (jet boat) wont start

Do you have spark from the coil? Pull the coil wire out of the center of the distributor, hold it about 1/2" from a good ground and crank the engine over.
You should have a nice blue spark jumping.

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

I didn't do that as I was by my self so I took a multi tester and put it on the positive of the coil and put the neg of my tester on a good ground and that had full power.

 

[wire2]

Re: Chevy 350 (jet boat) wont start

I didn't do that as I was by my self so I took a multi tester and put it on the positive of the coil and put the neg of my tester on a good ground and that had full power.

That's ok but it doesn't verify you'll have spark.
The neg side of the coil must be pulsed to ground AND the + side maintain 7-10 volts.

Prop the coil wire close to the block with a paddle or something and crank it to see.

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

wont be able to work on it anymore tonight so I will try when I get off work tommorrow and let you guys know then. if anyone has any other ideas let me know ill try them all at the same time, thanks. this site has been very helpfull

 

[Don S]

Re: Chevy 350 (jet boat) wont start

Click here

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

sorry it took me so long to get back but I checked and I have no spark from the coil wire. does that mean that i need a new coil? or could there be something else

 

[cooter2506]

Re: Chevy 350 (jet boat) wont start

If you verified voltage to coil but no spark then replace coil

 

[Dive Taxi]

Re: Chevy 350 (jet boat) wont start

What distributor is installed on the engine. I it is older, with points, check them first. ANY short from the coil to the distributor will keep it from working... Coils do fail, but it is unusual.

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

ok guys, im at a loss now. I put a new coil on yesterday thinking that the engine should fire up now or at least try to light on a coulple of cylinders how ever I had nothing. pulled the coil wire and tested it for spark and I dont have any. I verified power to the coil again. so now im stuck. could it be that I have a bad ground and if so what is it grounded to. I have two wires on the negitive side of my coil one is going to the back of the distributer the other to where the circut braker is. any suggestions would be helpfull before i go in a wild goose chase checking all the wires.

 

[searay3]

Re: Chevy 350 (jet boat) wont start

As was stated, any short in the negative side would stop the build/collapse of the mag field of the coil resulting in no spark. The second wire would go to the tach, but I'm not sure why that would have a breaker on it. Remove that wire, try again and look for spark. A shorted tach will kill your spark. If that checks out, I would replace the points. They can short as well.

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

the second wire is not on its own breaker, it is on the main breaker on the back of the engine. also I do have a brannew set of points in the distributer. I will pull the tack wire off and see if that does not do anything for me

 

[searay3]

Re: Chevy 350 (jet boat) wont start

I'm not understanding....my one brain cell is cloudy today...There should not be a power wire on the neg side of the coil. It is the ground side. If there is a power wire there, it is causing the breaker to blow anyway. Remove that wire. It's too simple a system. Power to the plus side, neg side to the distrib points and tach. Condensors have shorted and killed spark as well. Just because the points/condensor are new doesn't mean much. Had plenty over the years bad out of the box.

 

[coastalcruiser]

Re: Chevy 350 (jet boat) wont start

make sure the drive is in neutral?
and the neutral cut off wire is connected properly to the coil and your shifter?
Take a manual and look at the schematics all the wires for you engine are there and will tell you where any circuit breakers should be.
to find a short what I do is turn off the all power to the boat and take an alligator clip hook power to the selected wire, go to where it ends like the tach and test the end.
, should be the same voltage.
when testing for spark I just put a spark plug in the boot and touch it to ground you will know right there if you have spark to the engine.

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

The nuetral swich would not be the problem as i do not have one. its a jet drive and powers is always going to the impeller like a jet ski. I tried taking the tach wire off and I replaced the wire between the negitive and back of the distributor. If the points had a short. where would I look at on the points to test them. to be honest Im about to call it quits for this season and just pull the seats and the engine out and rewire the whole boat. I could have the engine and the seats out in about an hour or two.

 

[searay3]

Re: Chevy 350 (jet boat) wont start

It's been a while since I've had to deal with points. BUT..the contacts are a switch. One side of the contact is insulated. The one that comes from the coil, the other side is grounded. Using a meter, with the points open. If you show continuity on both sides of the points to any good engine ground, (bracket, bolt, etc.) they are shorted. Don't forget that condensor, they also short. It will run without the condenser, but will burn the points in short order. (hours not minutes), you can pull it if the points check out and see if spark returns. If it does, get a new condenser. There is another possibility....where the wires go into the distrib. If they have rubbed through, they can short as well. Gotta have an insulated line to one side of the points.

 

[rodbolt]

Re: Chevy 350 (jet boat) wont start

its easy,negative meter lead on a known good ground,positive on coil negative.key on points closed. should read 0 volts as if points are good there will be no potential difference much more than 0 volts go find the open,points open you should read about battery voltage,if not go find the short.
like it was noted, the points are simply an on/off switch. the condenser simply aids in keeping the points from arcing to to inductive ringing.
points closed current flows from the coil primary+,through the windings,out the - and to the points,through the closed points to ground. when the points open current stops,magnetic field in the coil primarys collapses into the secondaries and can develop up to 20K or so volts on the secondary side.

 

[Benny1963]

Re: Chevy 350 (jet boat) wont start

change over to hei rmove resistor wire if it has one and use ign hot wire
willsave you probs later they are foolproof and cheap 100 or so dollars
proform makes a cheap one ,
the distributer king on ebay sells chep marine heis
b1963

 

[Chad D]

Re: Chevy 350 (jet boat) wont start

SHE STARTED! found the problem, the copper strap from the point was not sitting right and was causing a short. fixed that and she fired right up. didn't sound great but I know what that is. its a fuel issue that I will post in another thread. thanks to everyone who had a reply.