East Coast B

I still put my money on something electrical.... as it seems to be just like our problem, only pops under load. Since it's not the wires, did you try going back to the other old parts? Plugs, cap??? It's a pain, but the only way to troubleshoot and isolate the problem.... are you getting to full wot rpm as in the past??

sonic28

full wot but still pops.im going to start a parts swap from the other motor.

sonic28

eastcoast
you lose.went to the boat tonight checked everything again.even took the plugs out to re check the gap compresion tested each cyl.put it all back and ran it in neutral 3500to 4000 all of a sudden no noise motor just shuts down from 3000 rpm and just spun untill it stopped. pull the valve covers off no damage that i could see.no milk in the oil or cyl.then i tried to crank it with out the plugs cranked beautiful but the rockers werent moving.my guess cam broke. will pull the boat out tuesday and start tearing it down.only 45 hours on these motors. any body want to guess cam chain gear?and how much damage.i feel lucky that i didn't hear a bang could have save the heads and lower end.

East Coast B

Sorry to hear the bad news, that really sucks..... Your problem sounded just like my buddies, put all new electrical parts in and started hearing popping at a specified rpm...... unfortunately you weren't as lucky as it being something minor...

Hope your back on the water soon!!!!

Pwrbt33

Sorry to hear about your motor! That always sucks! I have seen the cam break but you had a popping sound for a little while right? I have seen also where the cam bolts have come loose and timing actually changed until the gear broke or the chain broke. Are all the pulleys moving when you crank the engine over? I have also seen the crank break just behind the #1 and #2 journals as well. At any rate, sorry to hear about it!!

Keep us updated.

John

sonic28

thanks guy's. will no later the extent of damage.but i will tell you i will be boating this weekend as long as the its just in the cam area and not the lower end as well.what can i say you play you pay.its all in the fun of boating.i have to think positive.ive been boating over forty years.this is minor

MILD THUNDER

I had a cam go flat in my old 454 mag. It sucked. A little popping turned into a lot of popping. Hopefully you didnt get much metal in the bottom end from the cam. Find out the cam specs, have it overnighted, and swap that thing out. It can be done. I had mine apart and new cam in in two nights, buy my rea seat came out fairly easy. Good Luck!

BajaRunner

Mine did this one time, twin 350's, it was the fuel filters in the carb. i dont know why it popped, but it did, at about that same rpm. worth a shot, there only a couple of bucks each.

sonic28

the answer.#1 and number 4 cyl sucked a valve.broke the timing chain and the sproket on the crank.never touched the pistons.and the weard thing is no trace of water.may be to much fuel and didn't burn?but the good thing is i'll be running this weekend.

Pwrbt33

Great to hear that you'll be on the water this weekend....sorry to hear about the carnage.

John