Took out the Marlin this morning and idled up the river to the intercostal. When I opened up the throttles the starboard engine would not go higher than 1300 rpm in gear and 22 in neutral. Ran fine, no overheat, just wouldn't throttle up. Mechanic said its either a spun prop ( he didn't think that was it) an electrical problem, a cable problem or gasp......a blown power head. Damn! What do you chaps think? They are the old Yamy 250 smokers.
Engine Uh Oh......
- Thread starter Hookster57
- Start date
If they are 2 strokes, I would check the low pressure fuel pumps first. Sometimes they get small cracks in them. If not these, check filters including VST. Had same thing happen on my 225 once.
thanxI'd take a look at the low pressure pumps also. You could pump the primer bulb while the engine is running. If you're able to get the RPMs up I would change the pumps. There may also be spilled fuel once you squeeze the bulb enough.
Sounds like carbs, my buddy has the 225's yamaha's on his 93 sailfish. Seems every other year needs to rebuild the carbs. You can check the compression yourself, that would tell you if you have a blown motor.
First off find a new mechanic. If he thinks it could possibly be a spun prop or maybe a blown powerhead, they have no idea what they're doing. If you have bulbs, have someone squeeze them as someone give it throttle and see if the motor has power again. If that gives the motor the missing power, change the pumps. If it's an OX-66 how long has it been since you changed the filters?
I called him while I was onthe boat and he was just taking guesses. I had the engines tuned 20 hours ago.
Looks like we got a spammer here.
Looks like we got a spammer here.
No alarms? Motor sounds like it is in safe mode. It is not spun props. If the mechanic thinks it is, you need a new mechanic.
A spun prop will cause the revs to got high without a corresponding increase in vessel speed.
I need to know what model motor this is to diagnose further.
A spun prop will cause the revs to got high without a corresponding increase in vessel speed.
I need to know what model motor this is to diagnose further.
As far as I know the only safe mode is low oil and there should have been an alarm. It may have just been tuned but the OX's have quite a few filters (5 or 6) but if you never changed the low pressure fuel pumps that's my bet.
Grog said:
I agree it's probably the low pressure pumps. Squeeze the bulb enough and you should see some fuel leaking.
Great news. They found a stuck butterfly valve on one of the carbs that was affecting them all. It's fixed and only cost an hour labor!!
If it is an OX66, there are no carbs. There are throttle bodies but all throttle plates are linked together. If the throttle was not opening up, then you would not have been able to fully move the throttle lever. So, what really did happen here?Hookster57 said:
you may have lost fire spark on one bank of cly that motor has 2 charge coils on the sator one for each bank of cly it will start and run on 3 cly but will not turn up rpms I am a cert yamaha tech from 1985 to date I am head tech at grady white yamaha dealer in south fl I have been a tech for over 30 years call me if you need 2 239-348-8476
Hookster57 said:
The bottle has ratioes to mix listed.
I use it in all my engines. Keeps fuel system clean.
I'm a believer.
Same with Yamaha Ring Free Plus.