Cheap oil causing poor performance

[Fronterra]

In the past two months I have owned 2 different 2 stroke engines, a 1989 Mercury 25 hp and 1986 Evinrude 9.9. Both engines ran good and strong for the first 4 or 5 uses then both engines started having issues of running rough. The common denominator is the type of oil I was using in the mix which is a super tech tc-w3 oil that is cheap to buy. Could this cheap oil be the reason my engines ran poorly after about 4 or 5 uses? Has anyone ever had this issue that was fixed by using better oil?

 

[nwcove]

Re: Cheap oil causing poor performance

i prefer to run higher quality oil, but have never had any issues running the cheapest stuff on the market. maybe water in your fuel?

 

[Fronterra]

Re: Cheap oil causing poor performance

i prefer to run higher quality oil, but have never had any issues running the cheapest stuff on the market. maybe water in your fuel?

I checked the fuel, no water in it. I am scratching my head here because both engines had issues at the same interval of use.

 

[boobie]

Re: Cheap oil causing poor performance

Goofy question. How did you check your fuel for water ??

 

[Fronterra]

Re: Cheap oil causing poor performance

Goofy question. How did you check your fuel for water ??

I mix my gas and oil in a seperate 5 gallon tank then pour what I need into my boat tank. I had a little bit of the mixed gas in my 5 gallon tank and poured it into a mason jar and checked for water intrusion. When I had the 25 hp I got gas from one gas station and then I got gas for my 9.9 from another station. It would be seriously unlucky if I got watery gas from 2 different stations..... lol

 

[coolbri70]

Re: Cheap oil causing poor performance

how much oil are you adding per gallon?

 

[boobie]

Re: Cheap oil causing poor performance

Okay, you checked your fuel corrrectly. As long as the oil is rated tc-w3 I think you should start looking for other probs. Compression, spark and carbs.

 

[Fronterra]

Re: Cheap oil causing poor performance

how much oil are you adding per gallon?

I am doing a 50:1 mix.

 

[Fronterra]

Re: Cheap oil causing poor performance

Okay, you checked your fuel corrrectly. As long as the oil is rated tc-w3 I think you should start looking for other probs. Compression, spark and carbs.

Ok. Just funny how both engines ran about the same amount of time and had similar issues. Maybe I am the most unlucky boater ever....

 

[coolbri70]

Re: Cheap oil causing poor performance

that is a pint (1/2 quart or 16 ounces) per gallon?:redface::facepalm: i meant 6 gallons

 

[nwcove]

Re: Cheap oil causing poor performance

are you using two separate remote tanks, or one internal tank for both?

 

[Fronterra]

Re: Cheap oil causing poor performance

that is a pint (1/2 quart or 16 ounces) per gallon?

50:1 mix requires me to add 12.8 ounces oil in my 5 gallon tank.

 

[Fronterra]

Re: Cheap oil causing poor performance

are you using two separate remote tanks, or one internal tank for both?

Each engine had it's own tank. I use a 5 gallon tank to mix my oil and gas then pour my mix into a seperate tank for the engine. My 9.9 has a 3 gallon tank that I use.

 

[coolbri70]

Re: Cheap oil causing poor performance

what rpm do you run? how long are the outings? are the plugs fouling? what's the compression?

 

[Fronterra]

Re: Cheap oil causing poor performance

what rpm do you run? how long are the outings? are the plugs fouling? what's the compression?

I use my 9.9 to get to my fishing spot then I use my trolling motor majority of the time. It takes me about 10-15 minutes of high rpm getting to the spot then another 10-15 back to the dock. The plugs are not fouled, and with both engines, they ran great (good compression) for the first 4-5 fishing outings then both started acting up after about the fifth outing. It may be coincidental that both engines acted crazy with the same amount of use but something is telling me that I am doing something that has caused both engines to do the same thing at about the same time.

 

[Tim Frank]

Re: Cheap oil causing poor performance

The problem may not be in your Jerrycan....irt may be an accumulation in your in-boat tanks.

From another thread:

I'm going to suggest that before you do anything else that you check your fuel quality.
Disconnect the plastic housing at the fuel pump.Get a glass jar and using the primer bulb pump 2-3 inches of fuel into the glass jar.
Let it settle and see what you have.
I just have a gut feeling that there is a lot of crud and water in your fuel.

I've had this problem a few times....water gradually builds up in the bottom of your tank until it reaches the fuel pickup.

Easy to check and rule out...or check and fix.

 

[johnson89]

Re: Cheap oil causing poor performance

i have used super tech oil for the past 20+ years 55hp.225hp,140hp,90hp and have never had and engine problem from the oil,I still have the 90 ,all others sold were still running great..................

 

[the machinist]

Re: Cheap oil causing poor performance

This year I have had basically the same situation, and with 2 different motors, a 1984 6hp & a 1992 9.9hp Johnson & with different tanks & using NON-ETHANOL gas. Both are used as a "get there motor" but also 90% for trolling. The oil I was using was semi-synthetic sold by a national major marine store & purchased 8 years ago, using the ratio of 75-1.

After 3 full days of fishing the plugs fouled out badly on both. Previously on these same motors, using Penzoil TWC-3 standard type oil at a ratio of 50-1, I could get at least double the run time before having to change plugs.

Also the 6hp was decarbed before using it this year.

In doing some research, for semi-synthetic oils even though they are listed as TWC-3, no manufacturer gives the ratio of percentage of regular/synthetic oil mix for the blend, so it could be anywhere from 10% to possibly 70%.

So,I have to agree with the original poster, there is a distinct possibility of the mixed oil effecting a motor's running.

 

[ondarvr]

Re: Cheap oil causing poor performance

So just switch to a different oil for a couple of tanks, you will know for sure then.

 

[Fronterra]

Re: Cheap oil causing poor performance

So just switch to a different oil for a couple of tanks, you will know for sure then.

Thats the plan.