Possible Bad Gas/Fuel Delivery - Thanks SP

A few weeks ago I stopped at a fuel dock near the manasquan inlet. They where out of regular, but had premium, I usually use regular, but decided to have them fill my 80 gallon tank, took about 65 gallons. (Added Startron)

Since that time I had noticed that my usually very dependable 2001 Mercury 150 2-stroke was taking alot longer to start. I actually took the boat out last wednesday just to run it hard for an hour or so to "clean it out", seemed to run ok, but still hard starting.

Went out this past sunday and fished many spots from the seagirt reef, down to the pipe and out to the Carlson. After a few drifts I stated noticing that it was taking alot longer to start up. At one stop, I couldn't get it started, tried for 20 minutes and called tow boat.

Each time I noticed the ball was not full, and pumped it several times with no luck filling it up.

Contacted a friend on VHF, said he had a problem with a valve on top of his fuel tank, I tapped the fitting several times and seemed like the ball filled up.
It started up, I cancelled the tow boat and headed home. The inlet was crazy with the large swells and plenty of boats, made in with no problems. I ran the 3 miles to my slip, and just before entering our dock area she dies again. The ball was still full this time and could not get it to start, no matter what I did.

A State Police boat was near and came over and towed me right to my slip. THANK YOU!

Any ideas if this may be bad gas, a bad fuel tank valve, bad primer bulb?

Thanks

John

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

If it was bad gas I doubt it would be starting back up period and would run very rough. Could be as simple as the bulb. Have you checked inside cowling around the carbs or intake to see if there are any fuel leaks?

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

No Fuel Leaks..
I had a chance over the weekend to try a few things:
1. Changed mercury fuel filter, the one I removed was about 1.5 years old, it was not clogged. (Still would not start)
2. Hooked up fresh gas from a different tank. (Would not start) Drained all old fuel from the lines.
3. Replaced spark plugs, the removed plugs where installed in April 2013. (Would not start)
4. Removed air cleaner and for some unknown reason it starts. Runs well at around 3000rpm, but I do notice a miss at idle speed. I ran it for about a 1/2 hour with the air cleaner off.
5. Turned off, and replace the air cleaner. Took awile but I got it started again with throttle lever abour 1/2. Ran again for about 5 minutes.
6. Shut down to replace the cowl. Would not start again??? Tried for about 15 minutes and gave up.

Anyone have any ideas? Carbs?

Thanks

John

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Is it possible you have an exhaust leak at the base of the powerhead? That would explain problems running with the cowling on.

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Thanks Chris, I will take a look and see If I can tell.

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Had the motor running yesterday, still seems like its missing.

I checked the compression last night, Port side T-115 M-116 B-115 Starboard side T-120 M-121 B-121.

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Is it fuel infected or carbed?

Did you check for an exhaust leak yet?

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Carbed,

How would I check for an exhaust leak?

Changed the water seperator filter and installed a new primer bulb.

What would cause the ball to not fill up when I am squeezing it? I know I have gas?

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Exhaust leak should be able to see or smell coming up from the leg.

You may need to have the carbs rebuilt, they could have a blockage in them. Check for exhaust leak before rebuilding carbs.

Have the carbs ever been rebuilt?

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

The motor is 2001 Mercury 150 Saltwater I have owned it for about 5 years and have not had them re-built.

What would cause the problem with the primer ball nt filling up?

Re: Possible Bad Gas/Fuel Delivery - Thanks SP

Primer Bulb Never Gets Firm

If you can fill the bulb with fuel but it never gets firm, you probably have a fuel leak downstream of the primer bulb. This could be a stuck float valve on a carburetor, or a fuel leak in the engine fuel pump. Many engines use a diaphragm pump, and if the rubber diaphragm has a pin hole leak, gasoline will be forced past it into the engine crankcase. It should only take a few squeezes to get a primer bulb to become firm.

If you have a fuel disconnect downstream of the primer bulb, disconnect the fuel line from the engine and see if the primer can now be pumped to firmness. If so, your leak is in the engine.

"I will try this"