Here's Johnny

I just recently bought a new (to me) Sonic 358 Diablo......the motors are Merc 575's. The boat will be here in a few days so I am doing a little more research before I take delievery. These 575's are the ones with no sight glass......are these the earlier models that have a dip stick and oil in the front and rear of the blower ....or do they have a sealed bearing in the back too. I have read that the later models with the bearing's in the rear had more problems. Can someone give me the scoop on this style 575.........another question I have is what oil and how much oil goes into each blower....... I have done many searches on the 575's but still havn't gotton all of the answers. Thanks in advance guys....................John

Pwrbt33

iTrader: (2)

Congrats on the new to you Sonic! Very nice boat. Yours may not have a dipstick in it. If you have a large hex nut on top then you will. There should be a 1/4" pipe plug in the top, or a dip stick, which is a vent and there should be one in the front of the case about 1/4 of the way up from the bottom, when you take the lower plug out the oil should be to the bottom of the threads just coming out. If you dont have a plug 1/4 of the way up then you can drain some by removing one of the lower bolts on the front cover. As far as the bearings in the rear of the blower they are sealed roller bearings, no oil. Now, the oil that Merc uses is high perf gear lube, the green stuff. Some people run mobil 1 or there specialty gear oil. As far as how much, its not much something like a few ounces. I'll try to find the amount if there is one.

John S.

Here's Johnny

Pwrbt33.....first off thanks......so your saying there is no preventitive maintenance that I can do to the rear side bearing except a rebuild before something happens.........and only an oil changes to the front side.

Pwrbt33

iTrader: (2)

Yup!, I started to tell my customers after 2 to 3 seasons to let me pull them off and send them out to have them rebearinged and the rotors checked. Preventive maintenance.

John S.

Here's Johnny

I had the motors scanned and they show up with just under 200 hrs........I plan on trying to make this season then pulling the blowers off to be rebuilt for the winter........am i taking a risk or do you think this is ok. I also had leakdown test done on both motors......great results too.....most under 10% and two at 15%........

Pwrbt33

iTrader: (2)

It sounds like they are in pretty good shape. I dont want to tell you to take them off and I dont want to tell you to leave them on either. Kinda feel them out, listen to them see if there is any noise coming from them. Also have the dealer look up the engine serial numbers to see if there was any warranty work done on the engines and or blowers. Some also had a problem with shafts and couplings in the snout.

John S.

GLH

Verify the torque of the bolts on the blower front and back, a friend with those had the rear plate lossen up (it was held by hallen headed bolts)and the blower seized.

Might be an isolated incident but checking those bolts is fairly easy.

Here's Johnny

The dealer who brokered the sale showed me a stack of papers of all the warrenty work done to these motors since new....I am waiting for my copies in the mail. I will take your advice and feel them out......and thanks again for your help

Here's Johnny

will do GLH...thanks for the heads up...... Keep the tips coming guys.......I will have plenty of time for tinkering through April and May.........

Pwrbt33

iTrader: (2)

Sure, if you need anything else just shoot me an email. Some engines have had to have the head gaskets done around 300 hours, then is when I suggested to have a valve job done and new springs installed for good protection.


John S.