SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

[97MACHZ]

CAN SOME ONE PROVIDE ME WITH THE PROPOPER GAP FOR THE SPARK PLUG. I HAVE A NEW SET OF CHAMPIONS BUT THE MANUAL IS UP AT THE LAKE. I PHONED THE LOCAL DEALER BUT THE GUY ON THE PHONE DIDN'T SOUND TOO SURE OF THE GAP SIZE HE GAVE ME.<br /><br />SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

 

[seahorse5]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Use QL78YC plugs gapped at .030". Your owners manual will say QL77JC4 plugs but the plug recommendation was changed about 10 years ago.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Thanks very much, I appreciate the quick help.

 

[steamboatwilly]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Seahorse,,I have a 89-150,vro, Ive always used QL77JC4 plugs.Are you saying I should use QL78YC.Thanks.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

ok, I PUT IN THE UP DATED PLUGS BUT I CAN'T SAY I NOTICED ANY PERFORMANCE IMPROVEMENT. IT MAY EVEN BE A LITTLE SLOWER. ARE THERE ANY CARB OR TIMMING CHANGES REQUIRED WHEN YOU SWITCH PLUG STYLES. ALSO, WHAT REASON FOR THE SWITCH? DO THE NEW PLUGS RUN COOLER/HOTTER OR DO THEY HAVE SOME OTHER PERFORMANCE UPGRADE? CURIOUS?<br />THANKS FOR YOUR IMPUT.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Here's the lowdown from the 7th edition of the Clymer manual published 1991 pgs XI and XII. The actual recomended plug and gap for a 1989 120 HP Evinrude VRO motor: (actual manual wording to follow - NOTE 2)<br />OMC recommends the use of champion QL78C plugs gapped to 0.030 inches. for sustained low speed operation.<br />For sustained high-speed use, OMC recommends Champion QL16V (non adjustable gap).<br /><br />There are many updates and tech notes, I would strongly recommend that anyone who wishes to update the plugs for the motor they have consult the latest edition of the shop manual.<br />Cheers<br />Mike

 

[Dhadley]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

James, be careful when looking at responses for motors different than yours. The motor in this thread is a V4 looper. You have a V6 crossflow. The extended reach (Y) plug hits in a V4 crossflow so I'm sure it'll be close -- too close -- in a V6 crossflow. The QL77JC4's are fine in your motor.<br /><br />The best place to look for plug guides (for Evin/John) is in the accessory catalog from BRP that comes out every year. It may even come out every 6 months. As the fuel changes, the plug recommendation may also.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Hi Dhadley, Is the information I quoted ok and up to date? It was the most definitive and up to date that I knew how to find. By 'BRP' do you mean Bombardier Recreational products? I did visit the site but did not see a catalogue that offered a plug comparison chart, is it always there? I would like to use the best plugs available.<br />Cheers<br />Mike

 

[steamboatwilly]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Thanks,Dhadley

 

[Dhadley]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

The catalog is a dealer catalog. I don't follow the aftermarket catalogs too much, if at all. You even have to be careful of the OE service manuals. Something produced 20 years ago will have that years recommendation in the manual but bulletins may have come out that changes that recommendation. Just like Seahorse mentioned.<br /><br />The P&A book I have has the same info Seahorse gives. The QL78YC or the QL16V surface gap plug. I believe you mentioned the Clymer suggests a QL78C which is not the extended reach plug. It will work just as the QL77JC4 will work. Its just not what they suggest.<br /><br />And yes, BRP is Bombardier -- the parent company of Evinrude & Johnson.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Dhadley, thank you for this information. I am fairly new to this forum and boating in general. My previous boat experience has always been as a passenger or operator of small aluminum fishing boats. I usually try to research anything I do but I have always found that anything involving any kind of motor to be subject to a lot of interpretation and experience. This forum is a great resource for trouble shooting.<br />Cheers again<br />Mike

 

[Dhadley]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Mike, the biggest thing is to make sure the set up is right on that V4 looper. They love rpm so dont be afraid to set it up at 5800-6000. Its got a rev limiter at 6200. (If ya wanna know how to by-pass that, its pretty easy)

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

You know what else they love.....gas! HAHA. This is my first summer with this boat and motor so I am still learning what is 'normal' for it and how to keep it in tune and serviced. Once I become a little more confident I may take you up on that limiter bypass. I think, currently, the motor only revs to around 5200-5400. I find the throttle responce a little slow, like the cables are stretched or something. Top speed with a QL78YC PLUG seems to be around 37-38 miles an hour (GPS) it seemed to be about 38-39 (GPS) with the older QL77JC4 PLUGS. I need to experiment with this a little more before I am sure. The motor is mounted on a 1989 Smoker Craft 182 Magnum 18 1/2 foot with a dry weight of 1035 lbs. I have a lot of fishing gear in it and my 8HP Honda Kicker as well as 4 batteries so this may be slowing me down some. My friends father has the same motor on a 1989 Sunbird 16 1/2 foot bow rider and he claims 55MPH. That is on a water speedo which is, at best, inaccurate. I don't know how he has the motor set up but I would like to verify that speed by GPS. I'll keep you posted.<br />Cheers<br />Mike

 

[Dhadley]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Theres definately room for improvement there. If you can, play with the height. The higher you go the less drag there is. That has to be balanced with prop bite naturally. Just as a guideline, if you can use all your trim range, you can probably go up some. <br /><br />The balance is another thing. With that much gear you need to move things around a bit to find the "sweet spot". Its kinda hard when position is limited by battery cable. <br /><br />The bottom line is, you can experiment with things and get it as good as it can be.

 

[seahorse5]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Originally posted by James Williams:<br /> Seahorse,,I have a 89-150,vro, Ive always used QL77JC4 plugs.Are you saying I should use QL78YC.Thanks.

The plug recommendation I posted was for an 1989 120 which is a looper motor, not your motor.<br /><br />The only factory recognized sparkplug chart is the one they publish each year in their parts and accessories manual. You can view a .pdf file of it from this link:<br /><br /> http://www.boatsetup.com/SparkPlugChart.html

 

[steamboatwilly]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Thanks a lot,seahorse.I didnt realise different HPs would be different. I do now.Ill try to keep my head out of my a**.

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Thanks for all the interest guys. SeaHorse, according to the chart in the link you included above, my 1989 Evinrude 120 HP 90 dergree V4 looper should be run with QL77JC4 plugs. The use of QL78YC plugs is only recomended in engines manufactured after 1993. I guess that I had the correct plugs in there to start with. It seems to make sense though because I had at least 2MPH more at top end with the QL77JC4 plugs. Still without all the interest I might not have gotten this far on my own. The help is appreciated and no learning opportunity is lost if you make use of what you learn. I am still open to ideas about plug applications if anyone has more to add. Good luck everyone.<br />Cheers<br />Mike

 

[97MACHZ]

Re: SPARK PLUG GAP - 1989 EVINRUDE 120 VRO OUTBOARD

Guys - SeaHorse, James, DHadley, especially - I made an error. I quoted above, NOTE 2 from the Clymer manual as being the note relating to the motor I have. Although I correctly quoted the note it is actually NOTE 1 that applies to my motor. NOTE 1 reads as follows;<br />OMC recommends the use of champion QL77JC4 or L77JC4 plugs gapped to 0.040 inches. for sustained low speed operation.<br />For sustained high-speed use, OMC recommends Champion QL78V or L78v(non adjustable gap).<br /><br />The long and the short of it is that every thing seems to be pointing to using QL77JC4 plugs for my motor (at least for my application - which is some water commuting but mostly slow to medium speed driving primarily, with a lot of trolling speeds as well). I hope this helps some of you and clears up any confusion I may have inadvertently caused.<br />Cheers<br />Mike