Motor dies then won't start

[legalfee]

1995 90hp had carbs rebuilt. Ran fine for two hours. Next time out after 30 minutes dies and won't restart. Started fine the next day. I thought it was water in the gas so I installed a water separator. Took the boat out yesterday it dies after 30 minutes and won't restart.

 

[pnwboat]

Have you checked for spark when it's acting up?

 

[777funk]

Also, it can have a clog somewhere in the fuel system (tank pickup strainer in tank>>fuel lines>primer bulb>fuel lines>fuel pump screen filter>fuel lines>carb. All of that can eventually plug with use. The pickup in the tank is where I'd start then work your way to the carb. Also, air can get in at any of those junctions (on the suction side the the fuel pump anyways).

The tank vent can also be a problem (too much suction and not letting air back into the tank). You can tell this by opening the fill cap and listening for an air rush then reclosing. Probably not but one more thing to check on the fuel side.

It's likely fuel or spark that's failing you.

 

[Jiggz]

Try troubleshooting with muffs for cooling water on the driveway. First, get a small spray bottle and fill it halfway with fuel-oil mixture. You would need a second person to do the starting unless you have a remote starter. Remove the air cover from the carb. While cranking spray a mist of fuel into the carb. If no sneezes or coughs from the engine, you have a spark/ignition problem. If it coughs or sneeze then you have fuel/carb problem.

I would also check the tank vent to make sure it is not clogged or kink.

 

[jerryjerry05]

Test the overheat alarm? Possible getting hot?
After starting, isolate the primer from the carb, pinch off the hose from primer to carb bowl, too much fuel can flood out the carbs??

 

[legalfee]

Test the overheat alarm? Possible getting hot?
After starting, isolate the primer from the carb, pinch off the hose from primer to carb bowl, too much fuel can flood out the carbs??

I don't hear the alarm. It's possible it's overheating and the alarm isn't working. I'll check the primer. I don't think it's the fuel tank because I tried connecting a smaller tank. If it's overheating will it automatically shut off?

 

[topgun3690]

No automatic shut off on these.....that's what the buzzer is for.....to warn YOU to shut it off. You can test the warning buzzer by grounding the thermoswitch with a screw driver to a spark plug with the key on.

 

[Jiggz]

I don't hear the alarm. It's possible it's overheating and the alarm isn't working. I'll check the primer. I don't think it's the fuel tank because I tried connecting a smaller tank. If it's overheating will it automatically shut off?

Do you have a clear fuel filter after the fuel pump? If you do, was it still at least half full when the motor died? Or the primer bulb being collapsed. If fuel filter is at least half full and the primer bulb being not collapsed most likely the problem is in the ignition system. But before jumping on it, make sure the compression is still good.

 

[legalfee]

The bulb is not getting firm and I don't feel fuel going through. Now my starter is spinning but not engaging the flywheel.

 

[Redbarron%%]

Clean the Bendix so that it moves freely on the spiral grooves. Also the starter has to "snap" when the solenoid engages so that the acceleration of the shaft spins the gear up and into engagement.
If the battery is weak or the starter dragging this will not happen.
Also if the engine does not spin the engine over 300 rpm the magneto will not reach coming in speed and the spark will be weak or non-existent and the engine will not start.
If the starter is weak it will not keep up as the engine goes over TDC and the compression bumps the RPM higher than the starter is trying to spin it.
By the way the Chinese starters are mostly crap.

 

[777funk]

The bulb is not getting firm and I don't feel fuel going through. Now my starter is spinning but not engaging the flywheel.

When in doubt, I replace the bulb and any fuel lines in question. Bulbs have check valves which can fail. The rubber becomes stiff with time (and gas drying out the rubber). I consider a primer bulb a 3-10 year item depending on if gas has ethanol in it or not.

The other issue can be fuel pump (diaphragm tears and pumps into crankcase) and float not sealing which is usually trash in the needle valve but can also be a float not floating (filling with gas) or leak in the bowl. You'd see a leak in the bowl.

Fuel pump diaphragms get stiff with age and eventually tear (leaking into the crankcase through the impulse hose). You can rule a leaking fuel pump diaphragm out by plugging the fuel line directly to the carb inlet and pumping. If it fills the bowl and shuts off, it'll firm up the primer bulb.

You'll unfortunately have to refresh some parts on your engine before it's useful. But it'll be worth it if you have good compression. I'd put a little 30 weight oil on the starter bendix and work it by hand up and down (with battery unplugged of course) a few times then just let it sit oiled. It may come back. If not, probably will need thorough cleaning.

 

[topgun3690]

Been using this type of OEM primer bulb.....the retail ones from Bass Pro and others don't seem to last. Ebay has em and they cost more but last a long time.

 

[legalfee]

Clean the Bendix so that it moves freely on the spiral grooves. Also the starter has to "snap" when the solenoid engages so that the acceleration of the shaft spins the gear up and into engagement.
If the battery is weak or the starter dragging this will not happen.
Also if the engine does not spin the engine over 300 rpm the magneto will not reach coming in speed and the spark will be weak or non-existent and the engine will not start.
If the starter is weak it will not keep up as the engine goes over TDC and the compression bumps the RPM higher than the starter is trying to spin it.
By the way the Chinese starters are mostly crap.

This is a good video on the bendix:

 

[jerryjerry05]

Over the years: people who buy the NEW Chinese starters end up having some kind of trouble with them.
Some of the ones I've dealt with the magnets break loose or break themselves or the bendix drops out too soon.
I've found that rebuilding the OEM starter is the way to go.
I buy the "Mercury" brush/spring kit. A bit more expensive but the results are worth the $$$
Bendix: unless it's slipping it can be used again and again.
If you need to buy one get the good ones.

When rebuilding sandblast if possible(remove the bendix or grit gets up inside and will kill it), use fine grit sandpaper on armature.
Use a GOOD grease on the worm gear, just a touch, White Lithium seems to work well.
Small amount of grease on the end of the armature.

 

[Jiggz]

"I've found that rebuilding the OEM starter is the way to go."
Another thumbs up for that statement.

 

[Nordin]

I agree from my experience.
You can rebuild a starter more then one or two times.
If the commutator are in good shape and the brushes don´t are so worn out that the copper cord has started to touching the commutator.
The bushings can be replaced if they are worn.
A machine shop will be able to make new ones in a lathe.
Rebuilding old quality starter are way more worth the money then buying cheap new Chines junk.

 

[legalfee]

I bought my starter around 5 years ago. I don't think it's a Chinese model. I'll check it when I get home. Up until now it's been good.

 

[Jiggz]

I agree from my experience.
You can rebuild a starter more then one or two times.
If the commutator are in good shape and the brushes don´t are so worn out that the copper cord has started to touching the commutator.
The bushings can be replaced if they are worn.
A machine shop will be able to make new ones in a lathe.
Rebuilding old quality starter are way more worth the money then buying cheap new Chines junk.

And there's aftermarket brush kit for these starters by Sierra - part # 18-5697 which goes around $20.

 

[kbh121956]

Most states have a generator and alternator exchange that does an excellent job at rebuilding old outboard starters. When you get it back, it looks new and they warrantee it. I would do a local search. My 1963 Merc 65 hp starter the bushings were shot. No starter for it to be found anywhere. Took it to them and the next day, I reinstalled it.

 

[legalfee]

I was able to break the bendix loose with a ratchet wrench and lubed it with lithium. It's an Arco I don't think Chinese brand. I was able to pump fuel up to the pump but it took a while. I ran the motor for around 30 minutes. Thinking now I may replace all the fuel lines.