Need some ideas - port engine noise
 

Just started - running along and I get a loud Pop. And a loss of revs. It honestly sounds exactly like if a plug wire wasn’t on and grounded out. It’s normally just one or two pops, loss of revs and then slowly comes back. Having a hard time getting it to happen under 3k rpm’s.

plug wires tight, distributor wires tight. 1 year old Daytona Sensors CD1 box so no crappy MSD box.

im at a loss. Going up to get a new battery because one of my Optimas isn’t good I don’t think- never shows more than 11.5v.

anyone have any thoughts or ever had something like that? I was leaning to electric based on the noise.

carbed NA 565’s with brand new fuel pumps last season….

Vacuum leak, lose signal to carb, lean, pop! Or a sticking intake valve. I had a rocker go bad and hang the intake valve randomly

Ditch the Optimas, I have a pile of them. It seems when one goes bad they take out others. They are not what they use to be.

"Pops" are usually a lean indicator. Lot's of things it could be. Just some diagnostic advice- just because something is "new" doesn't mean it isn't broken.

Almost 40yrs of Diagnostic advice from me: Fix what is known to be bad 1st, before you go off chasing possible non existent ghosts.

In your case: fix your voltage issue 1st.

Rookie: i’ve had no luck with Optimas either. Red, yellow, blue. Prob 30-50 of them betw me, friends, cust’s. ??? Moved on from them avout 15 yrs ago. They weten’t that good ‘back then’ either. Not many battery problems since getting away ftom them, even walmarts have been good. Lol.

Oh…..


https://cimg7.ibsrv.net/gimg/www.off...fc2ce2722.jpeg

My first red top was OK, but second red top and later a yellow top both died prematurely. No more for me either. Same with the Diehards. They used to be great batteries but not any more. Having good luck with Interstate marine batteries from Costco for last 8 years or so.

Be good to check fuel press while at WOT if possible.

brand new Jesel sportsman steels after I had an aluminum break last year. I pulled all valve covers to check for issues and didn’t find anything


I went back to advance and they gave me a new one (unfortunately we are on a friendly basis so I’m going to see if that brings me any resolve. Problem is that was the starbd batter that was bad and the port motor is my issue. Hopefully one bad battery hasn’t smoked the other, but the bad one showed just over 11v at FULL Charge.

WOT!!??!? I’ve never spun them over about 4200 or so…..

Went and spent the last hour giving things a once over. 1 of my front motor mount bolts (offshore mount to block) was missing and two were loose on one side. Rears both required a turn or more to tighten up. Scary….. wonder if as the torque came up to 3000+ the motor was just flexing up a bit and then as I came off a wave and it unloaded some if it was smacking down a bit and making that noise?

I swear it was electrical pop sound and seemed to lose revs for a bit. I will test in the morning. Just feels like an ignition box is bad (regardless of them being new)

interesting chart. Squarely in the red…..

I get it, (why would bad battery on other side do this?) but again, always fix known issues 1st.