Thought I'd put this up here, it could fall under the motors forum as well. I bought Tropheus' Avenger, and dropped a modded Zen in it. It seems to miss at various times while it's running. Last year, I replaced both coils, the isolator block, exhaust and carb gaskets, and put a stock 257 on it. The only thing I havent changed is the diaphram in the carb, it had been sitting a while, but only a few runs on it. It is set up with an IV bag purchased for this boat. Anyone have any ideas? This motor seems to go thru spurts of running decently, and then like this. I have attached a link to the video of it running on Sunday below. Thanks everyone!!!

:huh:

Are you running the zero drag seals? May be a pulse problem to fuel pump?
Is the screen still in the carb?
Doesnt sound so much like a miss

Oz - no zero drags on this one... The screen is still in the carb. I am letting off in the corners yet, but if you hear the brrr brrrrp brrrrr that's the cut out. Its more prevalent towards the end of the video - I actually started to bring it in, and decided to make a couple more laps and it was worse during those last laps. I still had 1/8 to 1/4 bag of fuel.

i watched the vid.and for me its hard to tell what the problem is without being there (for me)there r some things you can check for i think i had the same problem so i asked jack at j&g (i got a j&g top kit on mine)and he said he dont think it was the engine (i though it was)check all you setting , pipe , carb . to me it sounds like it is running out of fuel (for just a short time)so check your fuel bag for a air pocket you need to get all the air out of the fuel system.start with the pipe at 11 3/4 stright back from the spark plug.the carb setting should be 2turns on the low side and 1 turn on the hi side. after a hard run check the spark plug it should be a tan colorif you can try to make your stright runs a little longer ( close to 330 ft as you can).i do think you have a fuel problem.

Boatking - I thought it was fuel flow too, but havent been able to absolutely prove it. I did burp the bag, but with most of it just in front of the bulk head, I cant see how much air is left. I do need to rechech the pipe length; and I did check the plug after that run, it was slightly light so I opened up the high and low 1/8. I ran a third time, but no video, and the results were close to the secod run. I wish I could run a little longer in the straights, I guess I probably could go a little farther down, but I want to stay away from the bridge, and there is a dam down stream. The "if you cross the 400' marker you're gonna pay' buoys washed away when the water got high after a 10" rain storm a month ago! The fine is a flat $100 no matter the circumstances, btw. They patrol a lot,must be a money maker for them.

it sounds like you r trying.sorry but i did not know the law there and you dont need to get in trouble.on the carb setting you can go as far as 2 1/4 low and 1 1/8hi but i would not go any further. after them setting check the plug if it still looks lean then something is wrong in the fuel system. you may want to try another carb and see what it does r try to clean the one you got and put new gaskets in it(they dont like sitting up)try a new diaphram with pumo gas you might get some of that gas with allky in it and diaphrams dont like allky.just keep looking you will find it it may take you a wile but you will find it.for peace of mind i would change the fuel line it may have a pin hole in it.

Every suggestion helps! I would love to run in a larger area - it just isnt evident as to why I cant in this video. The other "pond" we run at is even smaller! I'm going to change the diaphrams on the carb. I'll also reset the baseline settings on the carb, they were left from the last time I ran this carb, until I changed them that day. Fuel line is another possibility - the bag and fuel system are new - but anything is possible. I made a tray around the bag with small eye hooks and rubber bands to hold it down, but there is wriggle room. Could the bag be jumping around as it empties and maybe cutting off flow? That was the thought that immediately came to my mind.

Am following this with interest. I am having exactly the same problem
with my Suicidal mod. AC Razor.It just started doing this last few times out
(just like the vid.).I have checked and tried everything I can think of.
Hopefully someone has some ideas.

Make a JUMPER WIRE from brass tab side of secondary coil back to engine case.
Unplug bullet connector between coils, lightly sand the bullet with @ 400 grit, do the same to female connector, make sure the two connect firmly and close down slightly the female connector if they don't. A daub of dialectic grease on connector also a good idea.

Close down the S/P gap to @ .015"-.018"

Thanks Scott. I'll give that a try.