1998 Mercury 75 oil injection adjustment? Break-in setting?

[dls322]

Hi,
I have a 98 Mercury 75hp OB on my pontoon boat. I bought it from the original owner who after he bought it, used it maybe once, then it went into storage. It runs great! Plenty of power, smooth idle, it just likes to smoke. Wife complains about it and i feel bad smoking out some people in the cove. I have had other 2 strokes so i know what normal 2 stroke smoke should be.
I read in the manual that there is a break in period adjustment that you can make that changes the ratio for the initial break in period. Any one have any guidance on this?

i had the motor gone over by the shop when i got it, carbs rebuilt and adjusted, and such and they said that it looked brand new, so i believe the previous owner about the usage.

Any suggestions or guidance?

Thanks in advance.

 

[b20]

Re: 1998 Mercury 75 oil injection adjustment? Break-in setting?

Standard requirement for break-in is to add 50:1 to the tank. That would effectively double the oil running through the engine. That is why you're seeing excess smoke. Once you have the 20 hours up, and you make sure the engine has been using oil from the engine reservoir, then just put straight petrol in the tank and leave the oil injection to the oil injection pump. I have also found that some of the cheaper brands of oil will smoke quite badly too... My preferred 2 stroke oil is Quicksilver's TC-W3...

 

[dls322]

Re: 1998 Mercury 75 oil injection adjustment? Break-in setting?

b20, thanks for the input. I have been using the oil injection from the beginning. I have heard there is an adjustment that you can make to change the ratio. Supposedly there are 2 settings, break-in and normal. Was wondering if anyone else has gone through this.
Thanks

 

[Texasmark]

Re: 1998 Mercury 75 oil injection adjustment? Break-in setting?

I just scanned the serv. man. for your engine's big brother the 90. Only mention of breakin was a 25:1 note in Chapter 1, no time line nor how you do it. There is a linkage alignment comment about setting up the pump corresponding to carb linkage position elsewhere in the manual, but says nothing about that being associated with breakin. With the pump at idle the pump puts out a measley 80:1 as not much lube is necessary. At WOT it has increased to 50:1.

Easiest way to accomplish the 25:1 is as mentioned by adding 1 pt of oil to 6 gallons of gas during the breakin period whatever that is where you will have the pump output and the premix to double the oil percentage. If the dealer had maladjusted the pump vs carb linkage, where did he get his instructions and how did he know where to set it as there is only one alignment mark on the pump proper. Course that would require you to bring the engine back in for a post breakin adjustment; a thought for a dealer that felt he didn't have enough business, but I never heard of it. If the repair shop didn't know how many hours were on the engine he wouldn't have known to setup the linkage for breakin anyway, again IF there were such a thing.

Synthetic blend or synthetic TC-W3 greatly reduces smoking. Using Sea Foam to clean up your engine may be required also and wouldn't hurt since your engine has been sitting for a long time; very well may just be a little varnish keeping the needle valves from seating properly in the carbs resulting in a rich mixture even though the carbs were gone over. I use both and have very little smoke.

Other thing is that the shop may not have gotten the linkage setup properly which is tricky on these engines. However, I disabled my pump a couple of years ago due to age and use 50:1 premix with the oil/additives specified and smoking is almost non existent.
-----------------
In the fuel part of the manual on page 3c-8 they have an oil pump test:

Get a oil mix test tank at 50:1

Disconnect the output of the pump and divert to a calibrated container, plugging the line you removed to keep from messing up the fuel supply to the engine.

Disconnect the linkage to the carb linkage.

Attach an accurate service tach to the engine.

Run engine on test tank at 700 rpm for 15 minutes.

Oil in container shall be 18.7 cc min. at 79F. Different temps may result in lower oil level.
---------------

I think it easier to just get some clean fuel some sea foam and run the heck out of it for awhile and then see what happens.

HTH,
Mark

 

[dls322]

Re: 1998 Mercury 75 oil injection adjustment? Break-in setting?

Thanks for the expert advice Mark and for taking the time to check the manual for me. I will go the sea foam route and look into synthetic oil. I use the Quicksilver now, not sure if that is synthetic. I normally just use the boat in the "No Wake" river section of our lake. I don't think i have ever fully opened her up yet. When on the lake i normally run at 75%...Guess a good pick in the pants is in order!
Thanks for your help

 

[Texasmark]

Re: 1998 Mercury 75 oil injection adjustment? Break-in setting?

QK/Merc won't say. Pennzoil does, so when I buy my oil at WW I buy the Penn. Besides it's significantly cheaper.

Mark