Fouling plugs? Update 9/2/08

B

bassarama

Junior Member
Hey guys, long time no talk...

Finally I took the boat out for a shake down cruise and a little water skiing with the kids. For the first few runs the motor ran top shape topping of at 42 MPH on the GPS. After many stops and take offs and lots of idling, the motor started to idle a little rough and ended up losing top speed. I believe I fouled one plug and for a while it ran on 5 pistons only.
My hope is that I just fouled one plug due to all the excessive idling, after all, I pre-mix my gas at 40:1 ratio which may be a little to much.
When I first got the boat, (Fall of 2006) I did a decarburization using the “Seafoam” method and the motor ran perfectly fine for the entire 2007 season. Have any of you experienced problems similar to these, pre-mixing at 40:1 ratio?

Thanks

Joe
 
Last edited:
After repairing the ground cable for the starter motor, I proceeded with my plan of decarburization the motor with Seafoam. This is the second time I’ve done this since I bought the boat and once again I became amazed with the amount of white/grayish smoke it came out of that exhaust, that Seafoam stuff really works. I have a new set of Champions in and she’s running like a champ. All I need now is to find time to go fishing.:sun:
 
That 150 looper you have WILL foul plugs on 40:1 at low RPM's, not much you can do about it. The VRO ran them at 100:1-150:1 at idle to prevent plug fouling, but they would go to 50:1 at around 2000 RPM's and then to 40:1 above around 5000 RPM's. I would use a semi synthetic like PENNZOIL offers and mix it at 50:1. A regular dino oil at 50:1 will still foul plugs more frequently than a synthetic blend or a pure synthetic.
 
i used to use 100-1 amsoil synthetic blend in an old cross flow. Amsoil designed it to replace a 50-1. It worked real good, the engine idled good, but it didn't smoke enough for me, I always wondered if I had mixed the oil with the gas, or had mixed it correctly. Engine never had any issues from running it.
 

I’m starting a 50:1 mix ratio until I use all my Quicksilver oil, after that I’ll look into the semi or full synthetic oils. For safety purposes, I do quite a bit of idling when fishing at or near some rips (Race and the Gut) If I could cut back on some of the white smoke it would be great…

Thanks

Joe
 
PENNZOIL vs QUIKSILVER will definately cut down on your smoking some. QUIKSILVER is a good oil, but it smoked ALOT in every engine I've run it in.
 
Thanks
I added gas to the tank so I stayed closer to the 50:1 mixing ratio, last Sat. I went fishing with my neighbor and his son, we burned about 20 gls of fuel drift fishing and moving around, overall, I noticed a little less smoke and no fouling occurred.

One thing I notice was the lack of top speed, the max I could do was 33 mph.(usually 42 mph) Can’t figure out why…:head:

Prior to the trip, I installed a brand new set of Champions set at .030 gap. Did I buy bad plugs?


Thanks

Joe
 
You may have been running lean before at WOT. 40:1 will actually lean your fuel mixture out vs 50:1. At 40:1 your fuel is denser and slightly thicker which makes it go through the jets slower. 50:1 will fatten your top end out slightly.
 
THEFERMANATOR said:
You may have been running lean before at WOT. 40:1 will actually lean your fuel mixture out vs 50:1. At 40:1 your fuel is denser and slightly thicker which makes it go through the jets slower. 50:1 will fatten your top end out slightly.
Click to expand...


If I understand your theory, I’m supposed to gain a little top end speed at 50:1 because the fuel viscosity is lighter than 40:1, right?

This boat top speed has always been around 42 mph @ + - 5000 rpm’s. Saturday there were two adults and a kid plus all the fishing gear, the max rpm’s I could get was 4500.

Thanks for your expertise

Joe
 
No, the other way around. 40:1 is thicker so it takes more to pull it through the jets, so in turn less goes through. Also as there is more oil in the blend than fuel, every drop that goes through has less fuel in it at 40:1 than 50:1. 40:1 vs 50:1 doesn't sound like much of a difference, but when working with loopers it can be a big difference. I would still stick with the 50:1 mix and check your plugs to make sure you don't have one fouling out or something. Maybe try running your gap at .035.
 
update 9-2-08

Ok, got another bug out of the motor, after checking the new plugs with a precision gap gauge, I found out the old plugs were set at .035, that said, I set the new Champions at .035 and checked for fouling, all tested fine.
If you read above, last time I was out cruising around, I couldn’t achieve my 42 mph top speed…I had reduced the fuel from 40:1 to 50:1 and installed a new set of champions. The fact that a few days ago I had been working on the starter motor/ground cable, decreased the gas mix ration from 40:1 to 50:1 and installed a new set of plugs, this lack of top speed got my attention…

The throttle linkage was the obvious place to check and here’s the problem; as you can see, the missing piece of rubber sleeve is the reason the throttle linkage didn’t open the carburetors all the way, thus the lack of top rpm’s > speed:

WOT.jpg


As you can see, with the new slightly over size sleeve, the carburetors linkage opens all the way, there’s still about 1/16” of gap between the offset cam and the sleeve, this leaves enough play so that I can engage forward and reverse without accelerating right away.

gapbetweenspacer.jpg


Update: 9-12-08, plugs after running at WOT, 5500 rpm's:

9-11-08Plugsafter5500rpmrun.jpg




Here you go guys, a couple more pix for the record…:sun:

Thanks for helping out

Joe
 
Last edited:
Its amazing how when one thing goes a bunch goes and they have nothing to do with each other! Been there done that!
Glad you found it!
 
Is there any way to tell how much oil your VRO is sending the engine, and can you adjust in any way besides disconnecting altogether and mixing manually?
 
You must log in or register to reply here.
Back
Top