bravo

Hi,

I just bought a 91 Bravo for $150.00. Its a little beat. The machine will start up fine, but once you start driving (mayby 2 or 3 miles) it will start to loose power and then die. It will take about 50 pulls to get it started agian. Could this be a falty coil?
I also notced that the TPS is disconected. The local Yamaha shop said that the machine will be fine with the TPS disconected.
How much compression should this motor have?

Thanks for your help.
MJ

bravo

I made a mistake. Its not the TPS thats disconected its the TORS (Trotle override system). Its conects to the card and CDI unit.

LukeWilson

I think your right about the coil. Usually they work fine when there cold and when they heat up a bit they short or have a break in the wire. Also when was the last time the carb was cleaned.

bravo

I cleaned it a couple of days ago. There was a little bitt of stuff that was hanging up the float.
I checked the compression and its right arond 145 psi.
How can I check to see if the coil is bad?

LukeWilson

You should be able to test the coil using the specs in the manual, there should be primary and secondary resistances. The only thing is that it may not show up in this test. Usually coil problems occur once the coil is hot, not when its cold. Im guessing that you could get a new coil for less than 30 bucks and in my opinion its worth the try. If you know any sled salvage places, you could probably get one for less. Better yet they may let you bring the sled out and put one of their coils on and see how it works. The place near me lets me do that with electric parts, but i have spent lots of money there as well.

Goodluck, let us know how you make out.

bravo

I replaced the coil and it seams to run better. My new problem is that when cruising at a certain RPM the machine will ack like its throttle is stuck. I'll turn it off and it will still run for a few seconds. What do you think this new problem could be?

Thanks,
MJ

LukeWilson

It sounds to me like you have an air leak some where. Take your spark plug out and see what color it is, if its white or light gray your carb is out of tune or you have an air leak. It should be a nice tan brown color. Air leaks are commonly found in carb boots, the rubber splits allowed unmetered air in. It could also be crank seals, the only real way to check that is by doing a pressure test. Hopefully thats not the problem because it would mean that you need to pull the engine apart. Start by checking your plug, find out what color the porcelin is and get back to me.

Goodluck,

Luke

bravo

The porcellian is brown to black.

I was out in my garage trying things. I would start the machine on a stand and run it until it started to over rev and stay constant. Once I had know control of the trottle I would try to kill it. The machine will only die if I would hold the trottle wide open and turn off the key or hit the kill switch. It will not turn off unless I do that. I can turn the key all day long and it will just stay running wide open or hit the kill switch. I pulled the plug and checked for spark with the key out and the kill switch in the off position and theres no spark.
I think that its something to do with my electrical.

LukeWilson

Ok, good to here your plugs a nice color. I think your right about the electrical. Check the connection that comes out of the ignition switch were the key is. If that is loose or not connected, the engine will not shut off when the key is turned off. If thats fine it has to be something shorting out or a bad connection somewhere. Make sure there is no corrosion or water in the connectors, it may cause problems. There isn't to much wiring on a bravo so it shouldn't be too hard to find.

Goodluck

bravo

I took everything apart (electrical wiring) and found allot of rust and corrosion. I cleaned everything up and put dielectric grease on all of the connections. Anyways seams to be running right. Thanks for your help Luke.
I'll let you know if I come across another problem.
Mike