2008 Yamaha Superjet - Ported 61X not revving past idle

[misuperjet]

Hey guys. I already fixed the issue but I wanted to post the process I took, and what happened, in hopes it helps someone else in the future.

2008 Superjet
61X with JetManiac ported cylinder kit
ADA girdled head
Factory B Pipe
MSD CDI
Solas 144 Mag Pump
Hooker 9/15
Noco Lithium Battery

61X was idling fine and would change idle higher but when throttle was introduced it would not rev at all. Almost like a rev limited at 2,500 RPM.

This was a new build so I had to wait until I dropped it in the water and idled it for 5 minutes before I figured out there was an issue. According to JetManiac you should let it idle for 5 mins before you rev it or get it to half throttle. That was when we figured out there was something wrong.

Once back in the garage and cooled down, we went through this process:

1. Poured some fuel, using the primer, down the carb while holding the throttle open- Theory was to make sure it wasn't fuel related and the pop-off spring was set too high- This resulted in no change to how it was running (also be sure to have a plan in case the motor runs away on you)
2. Check spark plugs by switching them and then only running one wire at a time to see if it was the coil or wires- They both worked fine and both cylinders hit with no issues at idle
3. Change MSD CDI to factory- Just in case the CDI was bad or something. It came off a running ski but weirder things have happened before- Once changed to factory CDI it ran like a top!
4. Re-check compression and look for any air leaks or mechanical problems- did get there because we found the issue on step 3

It ended up being the MSD CDI. not sure if it was a mistake installing or if it just went bad. The ski this came out of had an unsealed electronics box. they left one hold open and there was corrosion inside it. I cleaned up the MSD CDI and made sure it had good connections in this ski.

Moral of the story, don't look over things just because they are new or worked before. You never know when things will break and in what order.

I try to have a neutral opinion when working on these skis and never assume something is good. Always verify everything is working properly before moving on to the next thing. The one time you get stubbourn about not checking something, it will be the thing that is broken.

 

[Half flip95]

Sounds like temp sensor circuit was working

 

[Pro-pulsion]

MSD strikes again. I've probably bought 6 or 7 of them over the years from new to used thinking maybe this time I'll get a good one but I've never had one last more than two years. Since they went bankrupt and came back to the market they've never been the same. A buddy of mine has an old school enhancer in both of his blasters from the mid 90's and both are still going strong. Anything before the early 2000's seems to be very reliable, anything after around 2009 just isn't there anymore. I remember watching the top fuel dragboat races in Wheatland Missouri about 10 years ago and MSD wasn't too commonly advertised but go back 10 more years and their name was on just about everything. Thanks to Wax Racing we have the modern replacement to MSD, the Zeeltronic. Mine has been good since I got it about 3 or 4 years ago. I'll never go back to MSD. If my Zeel caves, it'll be back to stock. I'm at a point in life now where max performance is not as important as reliability =)

 

[fastgtfairlane]

On the newer zeels they did away with the 10 pin connector which always the source of water intrusion if your ebox leeched water in. Ive had 2 fail and the 10 pin connector was the source. Been running my 3rd zeel for several seasons with no issues as long as your ebox stays sealed.

 

[misuperjet]

Sounds like temp sensor circuit was working

I must have missed that in the diagram. I had original wires capped off separately with shrink tubing inside the box.

MSD strikes again. I've probably bought 6 or 7 of them over the years from new to used thinking maybe this time I'll get a good one but I've never had one last more than two years. Since they went bankrupt and came back to the market they've never been the same. A buddy of mine has an old school enhancer in both of his blasters from the mid 90's and both are still going strong. Anything before the early 2000's seems to be very reliable, anything after around 2009 just isn't there anymore. I remember watching the top fuel dragboat races in Wheatland Missouri about 10 years ago and MSD wasn't too commonly advertised but go back 10 more years and their name was on just about everything. Thanks to Wax Racing we have the modern replacement to MSD, the Zeeltronic. Mine has been good since I got it about 3 or 4 years ago. I'll never go back to MSD. If my Zeel caves, it'll be back to stock. I'm at a point in life now where max performance is not as important as reliability =)

I have a Zeel in my 62T/61X build. I had issues with the carbs on it but i'm hoping to get that one on the water this week and test. If everything goes well, i will eventually get one for the 61X. I would like to have it reliable for the summer so I won't upgrade to that until close to fall, if I do.