2008 Yamaha F75 4 stroke HELP!!

[Eyefishalot]

I have a 2008 Yamaha F75 4 stroke. I winterized the boat last fall and stored it in a heated garage. Last month I de-winterized it, changed oil, changed lower unit gear oil and fuel filter. I ran it on the St. Croix last week and it ran perfect. The other day, I went to the St. Croix again, try to start the motor but it didn't fire. The motor cranks with a slow spin as if the battery wasn't charged. I repeated this a few times but no luck so I just used the trolling motor to fish all day. That day i went home and replaced the battery with a brand new one and took it to the lake, same problem. I still have warranty on the motor so I call the a shop and they said it could be my solenoid or starter so bring it in. I have no doubt the shop is correct but my only concern is why? How is this possible, this motor is VERY new. Does anyone have this problem? And can anyone tell me what I could have done to prevent this problem in the future?

[solbes]

I have a carbon copy of your exact motor. Wish I could help you, I haven't had any issues like that. Did you re-check the oil level? Safety lanyard still attached? I don't think you did anything to cause this, probably just a defective part as the dealer suggested. It happens, even with good brands and products. Good news is it will be taken care of.

One thing I would do differently is to at least change your lower unit oil in the fall, instead of the spring. That way if there is water in the oil it doesn't freeze. Might as well put fresh oil in the fall so you're all ready to go in the spring. Obviously these have nothing to do with the problems you've seen.

[Eyefishalot]

I drained everything in the fall and just stored it. Oil level is good, and safety lanyard is attached. I didn't hit anything or can think of doing anything to cause this problem. Thank god for the 6 yr warranty.

[Eyefishalot]

Thanks Solbes! I'm a little relief hearing that. Just wondering, i heard a lot of guys removed the air restrictor on the F75 and claims they now have a 90HP Yam... because the F75 & F90 shares the same engine, guts etc...Ever heard of this? This will void my warranty if anything goes wrong so I'm just wondering if anyone ever heard of such a thing or actually done it to their Motor.

[Deep_Sinker]

Thanks Solbes! I'm a little relief hearing that. Just wondering, i heard a lot of guys removed the air restrictor on the F75 and claims they now have a 90HP Yam... because the F75 & F90 shares the same engine, guts etc...Ever heard of this? This will void my warranty if anything goes wrong so I'm just wondering if anyone ever heard of such a thing or actually done it to their Motor.

In my mind this is very unlikely to get an extra 15HP just from an air restrictor. If so, why wouldn't dealers do that? I think you'd have to make at least a few more changes to the motor like the fuel system, timing, etc.

Best to get your motor in for diagnosis with your dealer. I'm sure that they will get you back on the water soon.

[marine_man]

It sure sounds to me like your mechanic is spot on, and is not related to anything you did or did not do during winterizing. While electrical components in general have a very low failure rate, you probably ended up with one with an issue. Should be a pretty quick fix.

As far as the restriction and 75 vs 90, check out this thread, where there was a similar discussion:

75 vs 90

marine_man

[solbes]

I'm not going to say anything concrete on the 75 vs 90 thing for one main reason, but I would check into it

[boatfixer]

I drained everything in the fall and just stored it. Oil level is good, and safety lanyard is attached. I didn't hit anything or can think of doing anything to cause this problem. Thank god for the 6 yr warranty.

I STRONGLY recomend refilling the lower unit in fall. DO NOT LEAVE IT EMPTY. There is no advantage to leaving it empty.

2 things

1. If there was moisture in there and you left it empty, it will be easier for rust to form. A full lower unit will have no air in it at the lowest point, which is where any water will settle.

2. If for some reason you forget to refill it in the spring, you will burn it up. I have some good friends who own a resort and to make a long story short, he used to leave stuff empty and an unforseen medical situation came about and while others were helpful in helping him, he nor them realized they were empty and 4 lower units were ruined.

Anyway, glad to hear its under warranty and the dealer I'm sure will take care of it.

[Eyefishalot]

Good point. Metal expose to moist & oxygen = rust. I will try it next fall.

[Eyefishalot]

I took it to the shop last night. The Service Mgr. told me its probably a starter or solenoid defect and they'll replace it under warranty.

[marine_man]

Glad to hear it.. thanks for the update!

marine_man

[Eyefishalot]

Another question I have for 4 stroke Outboards. One of the servicing guy tells me to use higher octane, premium gas and another guy tells me its not worth it. I'm confused...does it make a difference? I currently use 87 octane, what do you guys use?

Sorry, I'm a noob when it comes to boats...Anything will help.

[S.D. Ice Angular]

I have a Yamaha F115, little bigger same family though. I purchase new in 2007. I have never run a spec of alcahol through it and when I took it out 2 weeks ago for the fist time it started like we were just out the day before.

I am not saying that is/was your issue but I would look for a NON-Alchol fuel station in your area.

Keep us Posted on what your mechanic said was the issue...

[marine_man]

In my opinion, the majority of fuel related recommendations (unless your motor requires a octane higher than 87, which most don't) are made due to fuel stability or the lack there of.

I'm not going to recommend a specific octane. What I will tell you is that 4 stroke carb'd engines are very susceptible to plugged jets due to gummed jets or debris in the carb bowls from gas that isn't stabilized.

marine_man

[boatfixer]

X2 I agree