97 Challenger RPM/Plane problems (Plugs/carbs/...)?

[rgwekwert]

Hello,

I have a 97 Challenger single 787 engine that I am having a hard time getting on plane. I was only getting about 5500 max RPM and it was taking forever to get on plane but when on plane it would sometimes get up to 6000 rpm.

I checked the plugs today and found them black and fouled and with a gap of .033 inches. (I have pictures, if interested).

I am using the plugs and gap as defined in the specs for this boat. I don't have the plugs in front of me to tell the exact numbers (BR8EX?) but they are the ones in the manual ...

I put new plugs in and set the gap to .021. The boat initially jumped out of the water and got up to 7000 rpm for only about 5 minutes then the RPM slowly died and maxed out at 5500. I took pictures of the plugs after the 5 minutes, if interested.

After that - I played with the plug gaps .021, .025, .033, ... but can not get the boat above 4500 rpm now.

I guess I am wondering if this is just a carburetor problem or is it still a plug problem or something bigger. I just bought the boat this year so I don't have any idea if the carbs have ever been rebuilt.

I am fairly mechanically inclined but not sure I would do anything other than a minor screw adjustment on multiple carbs. I did put a new solenoid on today and that solved my flaky starting problems.

Thanks in advance for any suggestions. Any suggestions would be greatly appreciated


Bobw - Sent from my iPad using Tapatalk

 

[Waterluvr]

Each carb on your single 787 has an accelerator pump nozzle and you really need both of those in good working order to transition from the low circuit into the high side of the carbs. Nine times out of ten when I rebuild those at least one of the nozzles is obstructed and plugged.

Properly tuned carbs are vital to avoiding lean conditions and piston seizures, since you don't know the history absolutely rebuild the carbs, fuel pump and accelerator pump. Cheap insurance...

Clean the Rave valves to, those are an important part of the high rpm operation and transition.

 

[rgwekwert]

I know I've seen a couple people in the past who rebuild carbs... Is there a section in the forums that advertises these services? Any suggestions or should wait to have someone PM me?


Bobw - Sent from my iPad using Tapatalk

 

[rgwekwert]

Boat is back in business!!! Here were the remedies:
Carbs rebuilt and adjusted by Waterluvr (Thanks for the wonderful hospitality in Indiana).
Bucket adjustment: I have mentioned before the boat liked to start in Reverse, Well - I dont think the bucket was going all the way up. The bucket never locked up into forward. I had to adjust it at the throttle lever end.
I was instructed in the proper Rave Valve cleaning by Waterluvr. They were not bad (someone must had done them recently) but it couldn't hurt...
Throttle cable adjustments by Waterluvr.
The boat is jumping out of the water at 7500RPM and gets on plane in about 3s, then I can back it off and cruise at 5-5500rpm.

 

[Waterluvr]

It was a pleasure having you down for the day, we really got a lot of good time in on that boat and much accomplished. I hope you guys enjoy the rest of the season with it and can really put it through the paces next year.

 

[rgwekwert]

Oh yeah, the VTS was disconnected at the throttle levers too. I am not sure that kept me from plane but I guess you never really know which way it was pointing. So that was fixed too.
Again, the boat is resurrected and jumping out of the water.

 

[Coastiejoe]

Very good,,,

It is always nice to hear of members helping members...