First off - great forum! I have scoured it time and again and have found an answer to all of my questions except this one...I have an '87 Evinrude 40 VRO, (the serial number plate says it came from Canada) The VRO has been taken off of. This was done prior to my owning the motor. The motor was fouling plugs at an oil/gas mixture of 50:1 and having difficulty starting and running at low RPM's. I recently tried a 100:1 mixture ( I've only run the boat once since and used about 3.5 gallons of gas which is all it took to foul plugs prior) and the engine seems to be running a whole lot better. Its not fouling plugs any more, and starts right up and seems to run better at low RPM's. My question is, since this motor was once a VRO, is the 100:1 mixture safe to run, or am I going to do more damage than good. I also just had the entire engine serviced and the carbs rebuilt and the mechanic says 50:1 but can't explain the problems - not much trust in him...What do you think.
Howdy, 12meter.I wouldn't use 100:1. I agree with your wrench that 50:1 is the better mix for all-round use.Plug fouling, hard starting and poor idle may be caused by several tuning and plug selection options, but are unlikely to be caused by the difference of 1.28 oz. oil per gallon.Confirm that you have the correct Champion plugs, gapped at .030, correct timing and linkage to the throttle. Recheck float levels in both carbs and confirm that the jets are correct for your locale and 50:1 premix, rather than VRO operation.If you continue to foul the plugs, try gapping them at .040. OMC recommended .040 for many years for low speed operation.Remember that all tuning specs for that engine assume it is using the VRO.Let us know what results you get.
I switched to marine synthetic TC-W3 oil for 2003 and virtually eliminated the plug fouling in my two-strokes. I would NOT consider changing from 50:1.
The same guy that reccomended trying the 100:1 also said I might try using a hotter plug and 50:1. Would Changing the gap make the plug hotter or help to burn off the excess oil at 50:1? To note, I am extremely particular about the mixture...After inspection of the plugs at 50:1 they were black...After checking the plugs at 100:1 they were wet with a trace of oil but definately not black...Also, are there published information on settings regarding motors that have VRO's removed? I would think that the engines were engineered for the VRO and logic would seem to denote that some significant changes to the motor would have to be made after it is removed.Just wanna go fishin' - this motor has me spooked!
I have a '89 40m non-VRO & it never fouls out plugs. I use 50:1 gas & that includes a lot of trolling speeds. One pint to 6 gal. I would check for proper plugs.If it's running rich someone else should have a suggestion on how to fix.
I don't have the book in front of me, but if that engine uses the 3 jet carbs (low, intermediate, and high-speed) it's very easy for someone to get the low and inter. switched, and I've seen it happen more than once.There are several things that could be causing your problem....Low compression, bad fuel/oil, carb float setting too high, weak ignition, bleed-air passages plugged.If you run alot at lower power settings, gap your plugs to .035-.040.By the way, 100:1 is great for a kicker that never gets over 1000 RPM, but stay clear of it, unless you never go above a 1000R's.What oil do you use, and how do you mix it?????
It is possible that your carbs were running rich before you got them rebuilt. Now that they have been rebuilt they are most likely better. I would try using 50:1 again and see what happens. The engine has no idea if there is a VRO or premix, VRO just mixes the fuel and oil before the carbs, as long as there is premix in the crankcase and going into the combustion chamber the engine itself doesn't care how it gets there. Even with an operational VRO you would not be running at 100:1 at WOT, the VRO would be running at 50:1 at WOT so without oil at those higher RPM's you are going to do some damage. I would go back to 50:1 now that your carbs have been rebuilt, if it still does it try using different plugs or a synthetic oil. Good Luck.
The man that told you to use 100-1, hotter range plug, did he tell you to advance the timing too? if not, it's a wonder. This is a 1987 engine , before replaceing any parts or doing any work, do a compression, and ignition test, ckeck over the fuel fittings, and hoses. I'm always amazed at the time, and money that is spent on grooming a dead horse. There seems to be a lot of misunderstanding about fouled spark plugs, if you pull an engine back from wide open throttle, idle up to the dock, and pull the plugs, they are going to be wet with fuel, and oil, this is normal. If you are running on mixed gas, use 50-1, and the correct plug. If your engine is sound to begin with, and it is set up properly, it is no trick to make it run properly, but you have to start with the basics
I'v got a 1988 40 HP and its no problem running 1:50 oil/gas. For comparision, my compression is top 148, bottum 150 PSI. Great motor. It has fixed carb jets. Check that stator moving freely, and ignition advances as it should, and do sync'linck as R.Johnson says, its very important.
The man that did my carbs checked the compression and said everything was "within spec"(?) or he would not have bothered working on the motor... he said this was his standard practice... He also checked and fixed the throttle linkage, and was supposed to have checked everything else, I am hearing about alot of stuff here that I would never even have known about asking...he could not tell me what the compression was. Nothing was mentioned about advancing timing... What is the proper plug for this motor if what is in the manual is not correct for a motor without the VRO...I currently have the champion plug specified in the manual, can't give numbers as I am at work...
My comment about advancing timing was in ridacule, certainly don't do this. He took a compression test, but can't tell you what the numbers were? Why! How much have you spent to make this engine perform? I did not say "run". I would go back to this man, and ask to see his compression guage, and leak-down tester, also his service manual. If he has none of the above, run, don't walk to another shop.
OK - As I said - not much faith in that mechanic... I am currrently looking for a new one... At this point I have not spent much money on the motor itself... I have however completely restored the boat it is attached to... I have to say that when I do actually get the thing started it "performs" excellent at WOT... just runs rough at low rpm's and of course the plug fouling thing! Here's my plan... I checked the plugs last night... they were gapped at .033... I changed them to .035 as I do a lot of low rpm's and was suggested here... seems like a good middle ground to start.. I am going to switch to synthetic oil and go back to 50:1. I want to find the problem and fix it not kill the engine!The test run will be this weekend... As for the the hard starting... on a hunch I took my battery to be tested and it had lost a cell... not enough cranking amps!? Let's hope! Seems to easy... I am replacing and will let you know what happens...I'm not a mechanic and can only guess at alot of things... Thanks for y'alls input... I have some work to do... I will let you know what happens this weekend!
Location: Ankeny, Iowa, Sun Valley Lake, Iowa whenever possible:)
Posts: 335
Re: 1987 Evinrude 40 VRO 100:1 Oil Mixture?
Just a comment on the plug fouling, over-oiling thing.When I bought my used '86 40 hp/VRO, I ran 50:1 as well as the VRO until I was sure the VRO was working. It was, and even with the VRO supplying oil as well as my 50:1 mix, I had no fouling problems on two 6 gallon tanks of fuel I ran through the engine. The motor started good and seemed to run fine.Charles
Hi 12 Meter The only effect the battery will have is on your starter motor and charging system. It will have no effect on your ignition system ( spark plugs). Although a good idea to replace a defective battery, so you can have depenable starts. As Charles points out all new and rebuilt motors run double oil for the break-in period. It is also recomended that one uses double oil to test your VRO system. The oil is not causing the problem here neither is plug gap. What causes the fouling condition is too much fuel and not enough air. There are a couple of things that cause this condition. The most common is the carb not being set right. A missing part, worn gasket, something pluged up, something not plugging up when it is suposed to, etc. You say this motor has you spooked. Here's what you do. Go to the library and check out a manual. If they don't have one buy one. Read all about your motor and others as well. This will help you understand what's going on and your motor won't be so spooky. It will also help you decide which jobs you what to do your self and which jobs you would rather have a Pro do. Remember a few bucks for the book is a lot cheeper than blindly throwing money at the motor and praying.
1987 Evinrude 40 VRO 100:1 Oil Mixture?
Linear Mode
