Do I have Weak Spark caused by a bad stator?

[jstatham]

I got the QL77JC4 directly from the Manual. I guess they changed the recommended plug over the years. I will get the QL78YC but at this point I don't think the plugs are the problem. It is either a gas or firing issue and regardless I hope to figure it out this weekend. Thank for all the advice and suggestions. I will let you know what happens.

 

[Faztbullet]

BRP changed all the spec's in 1996... below is latest plug chart .Service manuals, are not updated and may be obsolete soon after printing, that's why you have to use the factory's annual Parts and Accessories Guide as the officail spark plug chart as it has the latest info. Back in around '95-96, OMC and Champion set about updating plug recommendations. They started with the QL82YC, but found out the 225 could not use that hot a plug. To keep things simple, they then changed all looper motors, 40hp and above, to the QL78YC plug.


http://www.boatsetup.com/Spark Plug Chart 2007 BRP.pdf

 

[jstatham]

I picked up 4-QL78YC today. I hope to get this headache figured out this weekend. Thanks.

 

[jstatham]

Hello everyone. I had a little time today and here is what I did. I put in 4 brand new QL78YC plugs gaped at .30. I then swapped the 2 top carbs and made a slight float adjustment. I then blew through the few inlet and verified that the float needle and seat were all working properly. I then fired it up and it still missed. While it was running I sealed off the fuel primer and that did not change the way it ran. I did some more investigating and when the fuel primer is pushed from the key it barely puts out any gas at all. I am thinking I have a problem with the primer but I don't think that is why it is missing. When I got the motor I did put a rebuild kit in the primer because it was leaking. Anyway after I ran it for I while I pulled out the plugs to check them out. They all seemed about the same and the brand new plugs where real black. Either they are getting too much gas or my spark it not hot enough. I know the stator is weaker than the specs but not sure if that the issue or not. Anyway will you please look at the videos and plugs and let me know what you think. I did not have a timing light but plan on getting one so I can test the timing and firing next weekend. Also at 1 point while I was running it it started sounding great for a few minutes then it starting missing bad again. I also noticed a bunch of steam coming out when I pulled out the #1 plugs is this normal? To me it almost seem like an electrical issue like a flaky power pack or something. Any help will be greatly appreciated. It looks like I fixed that one plug not firing but something is still not right. My iphone ran out of space or I would of had more video.

Running Rough Brand new plugs
http://www.youtube.com/watch?v=FxDib9V7pEQ

Steam On #1 Plug after 1st run with new plugs
http://www.youtube.com/watch?v=bds_EDpyPzU

Running Rough
http://www.youtube.com/watch?v=ydTqr8RDWns

Running a Little better but still missing
http://www.youtube.com/watch?v=-k6mdIT7c-g

 

[Bosunsmate]

Steam aint normal at all, read post number 18 again.
Try grounding plug number one ht lead out and see if that stops the missing.
Check the engines warming up as if its cold itl carbon up.
Are you running 50/1?

 

[Bosunsmate]

You either have a blown headgasket, blown exhaust gasket or cracked cylinder to have steam like that.
I wouldnt run it anymore until you know what it is as water getting on the bearings is bad news

 

[jstatham]

I am running 50:1 premix out of a temp can. Last time I took the plugs out the steam/smoke came out of a different cylinder. I guess which ever one is open is where it escapes. The pieces to the puzzle are starting to come together here. When I bought the motor there were no Thermostats installed and the lower crankshaft bearing was completely toasted and a hole blown through the crankcase.. I am beginning to think the block or something is cracked. Another thing I notice is when the motor is running I barely get a trickle out of the brand new water pump. I guess it is time to crack open the heads and hope for something simple.

 

[jstatham]

The more I think about the last time I ran the motor the smoke came out of the #4 cylinder. Wouldn't there always be some exhaust trapped in a cylinder when you turn the motor off and when you remove the plug it escapes? The old plugs were not rusty and the gas is not milky. I don't think there is a water leak.

 

[Bosunsmate]

The more I think about the last time I ran the motor the smoke came out of the #4 cylinder. Wouldn't there always be some exhaust trapped in a cylinder when you turn the motor off and when you remove the plug it escapes? The old plugs were not rusty and the gas is not milky. I don't think there is a water leak.

Exhaust aint steam. A new impellor and no water pumping can mean pressurising of the water jacket.
If you want to be sure drop the lower unit and clean your plugs.
Run the engine for about twenty seconds without LU or hose attached if it doesnt miss then water entering is your problem.
Thats the quickest and easiest way to confirm it.
Post a video of that

 

[jstatham]

I actually ran it without the water hooked up yesterday and it still ran the same. I am not sure if that gives the same effect of completely removing the foot.

 

[Bosunsmate]

yes, but if you had the LU still on then you have stuffed the impellor

 

[Tim Frank]

Has this motor ever run properly for you?
If not, I'd verify that the carbs are correct configuration for your model and some "expert" has not substituted parts to achieve extra "performance".
Pay particular attention to jet sizes.

 

[jstatham]

No I bought it used of Craigslist. All the carbs and part number match what the Parts Diagram show online for this engine. I know the jets match because I doubled checked the numbers to make sure I put them back in the right spot when I rebuild the carbs.

 

[racerone]

You now need to install a new impeller if it was run dry !!!

 

[jstatham]

It was still wet i just turned the water off with it running for a minute or so. It should be fine.

 

[Bosunsmate]

It was still wet i just turned the water off with it running for a minute or so. It should be fine.

thatl be over 1500 revolutions with no lube, thats quite some damage

 

[jstatham]

If I can get it running good I will be glad to change the impeller.