1995 Yamaha 225 2.6L: Again, rough idle, hard starting

[dmorela]

Hello Everyone

This is a follow up post to similar problem i had 2 weeks ago and thought I had it fixed with a new prime start system.

Here are the symptoms:

• Hard starting- once it fires it bogs down (like its flooded) and i have to rev it up to stabilize
• The idle is a little rough, with occasional surges. I don't see fuel in the water but the exhaust smells a lot like unburned gas
• when i accelerate from idle, sometimes (50%) there is a momentary hesistation between 1500 and 200 rpms. This passes and the engine runs great up to WOT no problems.
• After running for 30 minutes or more and I shut oit down to fish for a while the engine won't crank. I;m pretty sure it is flooded. I have to wait at least an hour before it will start again (same starting procedure as before).
• I know the prime start system is supposed to crank it up without the throttle advance being raised, but it won't on my engine.

Here is what I have done:
Cleaned the carbs TWICE
Replaced the fuel pumps (about 6 months ago) and the prime starter (last week)
New fuel/water seperator filter
New primer bulb

Not sure what to do next? Was hoping for a boat trip for Fathers Day!

Any insight would be much appreciated

Thanks

 

[rodbolt]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

sounds like your back to fuel issues

 

[dmorela]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

What else could cause it to flood after it is hot?

If I run it for 10 mins, shut it off, wait a few minutes and turn the key it fires right up.

If I run it for 30 min, under load, and shut it down, wait a few minutes it won't start at all. After 30 min or so, it will finally restart and will continue to run fine.

 

[dmorela]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

Just a thought, but could it be the thermosensors are bad so that after the engine is restarted after being run hard, the prime start is being enaged when it really shouldn't and the crankcase is getting flooded with fuel?

 

[rodbolt]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

could be a primestart solinod is leaking,the diaphram is damaged,another lift pump got damaged or a carb needle is leaking.h
when say wont start I assume it cranks normally.
when it wont start have you opened the throttle to allow more air? this would confirm an over rich mixture.

 

[dmorela]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

It cranks normally and yes, I have to advance the throttle to get it to fire.

The entire prime starter unit is brand new (I couldn't find a diaophragm in stock locally but the dealer had a brand new unit he gave me at half-price).

The other 2 fuel pumps are probably 6 months old. But I will recheck these.

When i rebuilt the carbs, the kit came with new needle valves so these were replaced on all the carbs. I never found any junk in the seats (or in the carbs in general).

Question- could there be a problem in the connections leading to the PS system?

 

[dmorela]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

Rodbolt
I rechecked all the lift pumps and they are good. Bulb gets hard and stays hard- I can practically stand on it and it stays tight. No fuel comes out of lift pumps or carbs so I think both the pumps and the needle valves are tight.

Another issue I noticed is that the engine doesn't appear to be charging the batteries. I've got 11.8 volts at the battery with no change after engine runs from idle to about 2000 rpms at the dock.

Could the lack of charging output be causing the prime start solenoids from staying in the open position and causing the motor to run rich all the time?

 

[rodbolt]

Re: 1995 Yamaha 225 2.6L: Again, rough idle, hard starting

dunno but ya gotta fix the charging system.