yamaha 225 4 stroke, 2004 model year

[99yam40]

if what you are doing helps for awhile then you know you are on the track of something, just need to figure out what it is that you are doing to help .
maybe do one thing at a time to see what is helping

[pstephens46]

Not saying the fuel you are buying is bad but there is a gremlin somewhere in your system. My F150 is not a miracle machine compared to your F225. Not that different....fuel issues are the only thing I feel are different. 5 years and I have had no fuel issues. None. I can't remember...has the tank been cleaned and all lines prior to engine replaced? I am not known for patience and I feel your aggravation.

[oldmako69]

Tank has not been cleaned. Orig lines I'm sure.

Old guy bought it new upon his retirement. Promptly had a nasty myocardial infarc. Boat went into storage in his massive garage. Several years of recovery later, he starts using the boat. Sparingly. Breaks back. Boat back into storage. So, sitting sitting sitting. Horrible for boats and airplanes.

So, here I come at 11 years. Boat has 125 hours and looks near new due to inside storage.

The fuel lines could be crap, and the tank as well but I'm changing clean filters and VST screens. Unsure why the RPM has fallen off. I'll keep at it and eventually get it dialed in. Hopefully.

[general5093]

Yamaha 225 reduced speed issue

I made another observation yesterday - I changed a coil that did not appear to generate a spark- the new coil has the same symptom- no flash when using a spark tester on plugs 1 and 4. No degredation in idle performance when plug boots are pulled from 1 or 4 while idling. Significant degredation occurs when I pull any other plug. Any ideas on why 1 coil does not appear to be delivering the needed spark? Wondering if the system engages these 2 cylinders only when needed?

[rodbolt17]

ever wonder why you have 3 coils 3 TCI inputs and 6 plug wires?
\ it is called waste sprk ign .
if you unplug a plug wire it wont spark and usually takes its mate out with it.
that is why I doubted a coil failure.
that is also why you have to spark test both pairs at the same time or like me, use a Kv tester.
dang pesky test equipment.

once I used my trusty Kv tester to verify spark I would move along to the most likely culprit.
Fuel.

typically on a waste spark coil if you lose one side you lost the other as well.

[fairdeal]

Rodbolt is surely correct.

However, just to mention:

[general5093]

yamaha 225 with slow speed issue

I doubt you found a bad coil.
however your symptoms are typical of a clogged VST filter.
all the fuel that motor burns goes through a filter about the size of a pencil.

I made another Sunday afternoon effort to work on my yamaha225 to address the slow speed (max rpm 4200) issue. As mentioned earlier, I previously changed the coil in the upper most slot. The old coil, and the new one have the same symptom - no spark is generated on plugs 1 or 4. I used a spark tester on the plug cables, no flash on 1 or 4 and a bright flash on all other plugs. When I let the engine idle, and pull the plug boot from 1 or 4, there is no degradation in idle performance. However, pulling the boot from any other plug brings a significant reduction in engine idle stability (and an occasional shock too, ugh). The prior posts have pointed to a fuel issue and no doubt I may have one. However, it seems odd that I see no spark from one coil and spark being delivered to all 4 other plugs. Any input on this? Could it be that this coil is selectively engaged only when power demands it? Or, should that one generate spark all the time? I may be running down a rabbit hole here....but, somehow, this symptom does not seem right.

[rodbolt17]

at the risk of being cruel.
no way to make 1 or 4 misfire by spark.
no way to make 1 or 2 misfire by spark.
the translator wasn't real good.
look at how the waste spark system works.
if you cut the input to one ign coil assy you just cut two cylinders.
if the shift switch is stuck you will never ever have a smooth idle.
it is easy to test, simply move the shift slide ,triggering the switch and listen for the rpm drop.
let it go and listen for the RPM to pick back up.
this stuff aint hard.
and remember,typically above about 3000 RPM the shift switch input is ignored.

[general5093]

yamaha 225 with slow speed issue

ok, not worrying about being cruel, I'm just reaching out for help to fix a problem that has been costly for me - 3 mechanics and hours of personal effort with 0 results.

so, the efforts I should be making are all pointing to fuel? is that correct? my next move is the F filter as per an earlier post; parts store was closed yesterday so I did not change that yet.

thanks again

[oldmako69]

Just pull it and stick a temp hose bib in there for testing purposes.

Has anyone come up with a suitable inline replacement?