Need to change spark plugs on VF90 outboard

AuthorizedUser

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I've begun the boat winterization process for the first time in my life. So far, other than hiccups which are expected as a newbie, so good. However, I am stymied by how to change the spark plugs. I do believe the spark plugs are behind this bar, but it's not like anything I've ever seen before when changing spark plugs. Does anyone have any guidance for how I am to proceed? Thank you.
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KC24

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Did you try googling it.
 

AuthorizedUser

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Those are fuel injectors.
That makes way more sense. However, I did look around the engine and I didn't see anything obvious that look like spark plugs. I will look again. Perhaps they are under the shroud. Thank you for the information.
 

AuthorizedUser

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Plugs should be in the back of the motor, under the coil packs. See this video, should be the same for yours:
I appreciate the link! At first glance, I do not believe my engine is completely identical to this one, however I will look more closely.
 

AuthorizedUser

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Did you try googling it.
Always the first thing I do. Having a difficult time trying to find my exact engine. YouTube was immensely helpful for changing my oil and my lower unit lubrication.
 

RangerMTB5

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I appreciate the link! At first glance, I do not believe my engine is completely identical to this one, however I will look more closely.
No problem, They should be similar though. Report back what you find.
 

AuthorizedUser

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No problem, They should be similar though. Report back what you find.
I absolutely will report back. I will give the crew a summary of my efforts. I had hoped to make a video of my winterization but since it's my first time, I'm so glad I didn't!
 

BigKahuna

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Just curious how many hours are on your engine? How many hours does Yamaha recommend for a spark plug change?!? I used to change my spark plugs religiously every year on both of our previous I/O's. (Also oil and lower unit grease changes) Then I met a marine mechanic when we first moved to NC who performed all of those tasks, plus winterization, and storage. When I told him to change the plugs (Iridium costing $15 a piece) he said, Why? Is it running rough, missing, backfiring or drinking fuel?!? I answered No. He said .... Then leave them alone !!! So I did ....
 

AuthorizedUser

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I think I have upwards of 85 hours from this first season. I hear what you're saying about the spark plugs, but since I had to take them off anyway to inspect them, why not throw new ones on for 9 bucks a piece? That was my rationale. Probably overkill, I'm aware, but if I have to go to the trouble of taking them off, might as well throw new ones on.
 

BigKahuna

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I think I have upwards of 85 hours from this first season. I hear what you're saying about the spark plugs, but since I had to take them off anyway to inspect them, why not throw new ones on for 9 bucks a piece? That was my rationale. Probably overkill, I'm aware, but if I have to go to the trouble of taking them off, might as well throw new ones on.
Yup you're right!
 

PartyBarge

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Considering the age and hours you have on the motor, I'd start by leaving them alone. Yamaha uses components that are good for way more than 85 hours. Consider this even at a road vehicle average speed of, say, a lofty 65 MPH, 85 hours is only ~5500 miles. No way would I recommend a plug change, unless there is a suspected problem (even if they were free).
 

AuthorizedUser

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Hey all... I found them! I feel so stupid even asking you fine chaps in the first place. I was so fixated on that one spot (the injectors), that I didn't do a closer inspection of the other areas of the motor. In my defense, I did have to pop a cover off to find them. They are so PAINFULLY obvious to me now. Thanks everyone (he says sheepishly). On a related note, the oil/filter change and lower unit lube change went well.
 
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AuthorizedUser

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Considering the age and hours you have on the motor, I'd start by leaving them alone. Yamaha uses components that are good for way more than 85 hours. Consider this even at a road vehicle average speed of, say, a lofty 65 MPH, 85 hours is only ~5500 miles. No way would I recommend a plug change, unless there is a suspected problem (even if they were free).
Well... I already bought them from PartsVu... and I have to take off the old ones... and if the new ones won't hurt anything... guess I'm using them. But, I do agree with your logic.
 

PartyBarge

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No biggie, you'll have a good set as backups (that will likely go unneeded for years). I changed the plugs in our 2004 motor in 2013 (I think) for no reason other than the old ones were original (I think) and wanted a higher tech plug. Went with the Autolite APP5325 double platinum (platinum tips on both electrodes). They've been in service every since. If I were going to change them today, I'd likely take a look at iridium for no good reason other than they sound like a cool nerdy upgrade. (really no need for a plug that will go the equivalent of 100,000 miles)
 

sunedog

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Don't change them then fog the motor! It will foul the brand new plugs. Fog the motor with the old plugs. In the Spring, I'd suggest running the boat first and if it runs like a Swiss watch, don't change them. If it hesitates, misses or otherwise doesn't perform as new, then change them.
 

RangerMTB5

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Don't change them then fog the motor! It will foul the brand new plugs. Fog the motor with the old plugs. In the Spring, I'd suggest running the boat first and if it runs like a Swiss watch, don't change them. If it hesitates, misses or otherwise doesn't perform as new, then change them.
I agree with this. That's how i've also done it with waverunners too. fog in the fall. change plugs in the spring after the first ride. however, i have yet to change plus on my outboard.
 
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