1997 Challenger Bogging

[nate_4_01]

Boat runs great except bogs down when I put it in forward and am going slowly (3000 rpms approx.) and then try to increase throttle. It wont let me slowly increase the trottle or it will almost die and sometimes does. i have to put trottle almost all the way forward and then it gets over the hump and goes great. anyone know what this could be? spark plugs are new, rave valves have been cleaned(although they could probably be cleaner), new gas, rave settings have been tried at both all the way in and flush(no difference really), compression is 130 on each cylinder. let me know what you guys think i can try. thanks!

 

[jhjesse]

Sounds like the Low speed mixture screws need adjusting. Probably clean the carbs while you are at it.

 

[nate_4_01]

how much would you recommend adjusting them? also clockwise or counter clockwise?

 

[nate_4_01]

do you guys think rebuilding the carbs would work in this case as well?

 

[jhjesse]

First of all I would look at the spark plugs. They should be chocolate brown. If they are black, then the mixture is too rich. If they are light ashen colored, then the mixture is to lean.

Next I would take a compression test. 150psi is near perfect. anything less than 130psi is cause for concern. Oh I see you already did that...borderline. Check your compression tester.

Counter clockwise on the LSA richens the mixture. Clockwise leans the mixture.
Download a manual and read.
If it were me, I would rebuild the carbs and set everything to factory settings. (Use only genuine Mikuni parts.)

 

[nate_4_01]

thanks jhjesse! i am going to start with cleaning and rebuilding the carbs. never done it before but cant be too difficult. i have a manual downloaded just in case.

as far as the spark plugs go. i will have to check them when i get home later. when i first bought the boat this year it fouled a couple plugs but i think it was from when they winterized it and from bad gas. i syphoned all the gas out and replaced with fresh gas(no ethanol) and have had it out 3 times in the last 2 weeks without any fouling. it runs great except for the bogging from going very slow to fast. i have just been gunning the trottle when i feel like its going to bog down and it hesitates a second and then goes.