Stutter or missfire after starting.

[MacSeaDoo]

Well, again I think I was chasing 2 issues.

Put the rebuild SC in this morning. Spent an hour or so running at all RPM's running this AM. Lots of stops, a couple of full 62 MPH runs. All great.

Heading back when coming into the bay, thought I saw something in the water so looped around to look. Couldn't find it, so pushed on the throttle and stutter, bog, stutter, bog. Pulled back, did it again same result. 3rd time it stuttered a bit then went as normal. Again no issue. Next time stutter and bog.

I am beyond frustrated.

Called the dealer and they only had 1 coil in stock. I put it on cyl 1 and 3 new plugs and now heading back out to see.

If it does it again, I will move the coil to cyl 2...etc.

Again, after the stutter and bog, it will go right to 8100 rpm. Never has done it steady state. Never has done it at mid to high RPM.

Just for reference here were the old plugs with 25 to 30 hours. Basically textbook perfect.

 

[MacSeaDoo]

BTW, I picked cyl 1 not because it was the first one. If you look at the plugs cyl1 is the middle one and it was slightly different than the other 2.

Went back out, so far no issue.

Time will tell.

 

[Digdog]

Is that rust on your plugs? Do you have an intercooler leak ? Just the way the deposits are coming off the end looks like something is not right.

 

[MacSeaDoo]

I don't think it is rust, it looks like carbon.

I know it looks like that from that photo

Here is a better shot. I did have a bad intercooler with a leak but I replaced that 20 hours ago.

 

[Digdog]

Are those the old plugs from before the intercooler leak? I too had an intercooler leak on my 260 , bought it that way and I don't know how many hours it was leaking before I bought it but I had about 15 hours on it before I changed the intercooler. 25 hours after that it cracked a piston so I had to rebuild the engine (used forged pistons). All of the exhaust valves were shot , they said it was from the water. If you changed the plugs you might try a compression test and a leak down test , but the plugs look like mine before I changed the intercooler.

 

[MacSeaDoo]

Man, that sucks about your cracked piston.

They were in there during the IC leak, I should have removed them after I replaced.

I have not done a compression check or leakdown because I can hit 8100 RPM'S @62/64 MPH no problem.

If I had a compression problem, that most likely would not be possible.

I do have an inspection camera so maybe next time I pull them, I will take a snapshot of the cyl. I almost don't want to look because was out oday for hours with no stutter. Before, it would often happen several times per day. It was either a plug or the coil on cyl 1.

Time will tell.

 

[Digdog]

You should change the plugs and see if the problem goes away , a compression test would also give you quick snapshot of the condition in the engine.

 

[MacSeaDoo]

I did change them along with the coil for cyl 1 and so far no stutter.