Ok so i have rebuilt my 951 rx millineum edition....Posted some threads on here over xmas and Seadoosnipe and kustomkarl helped me out with a couple of things..Thanks guys..So i took it out last sunday over here in sunny uk in the sea....I put a R &D flame arrester on her when i rebuilt...she now starts up off the button which she never has,even since i brought her.Ticks over nicely, give it some gas and there is like a flat spot ( no power)...Get the revs over this spot and she rips away....goes great no problem...The reason i put the R&D on is because i couldnt be bothered to put that great big old thing back on ugly thing......Was told that if putting r&d on i should up jet the carbs....so im gonna put the old big black ugly thing back on this week and try her back out a week sunday....What you think anyone,do you think this will solve the flat spot????....Other than this small problem im well happy with the rebuild....Nick
951 rebuild
- Thread starter nick.rx
- Start date
- Status
rebuild!
Glad Karl and I could help you out. I think he'd concure with me on your flame arrestor as the source of your flat spot. You can rememdy this two ways.......first, I had to go back through your post because I didn't know if you had the DI model, which you don't.
By changing the flame arrestor to the aftermarket type, you've allowed a greater air flow through the engine. This isn't necessarily bad. You can get a little extra horsepower this way. But you have to change out your pilot jets. Not to sure about your main jets since you say that once you get over that flat spot, she really goes!.......that's good.
The carb has three different working positions. First, the first few degrees the throttle plate opens, the low-speed screw is adjusted for idle speeds. Then, your next position is from those first few degrees to about 1/4, that's your pilot jet alone, then from there to almost wide open, your getting your fuel from the pilot and main jets. At WOT (wide open throttle), your fuel is basically completely through your main jet.
Here's something you can try if you don't want to put your old air induction system back on. Mark your set point on your low speed idle screw (so you can put it back if needed). Then, turn it just a bit to the open position. This will allow more fuel through the carbs at that slower speeds and may help get rid of that flat spot. If you notice a difference, open it a little more till you get it right.
One more thing, that big black box is designed the way it is so that it changes the direction of the air a couple times. For each time the air changes direction, the heavier water molecules drop out of the air and won't make it into the engine. You've eliminated that by the aftermarket flame arrestor. Also, if you are able to open your slow speed screw to take out that flat spot, then your running your engine a little richer in fuel which in turn means you need to have more oil from your oil injection pump delivered to keep the fuel/oil ratio in proper balance. I don't have to explain to you why, I'm sure you know that.
My personal opinion, put that ugly black box back on. You'll probably get longer engine life with it verses the pretty aftermarket type.
Sorry for the long post, sometimes, the extra information is needed to ensure you get a good understanding of what I'm trying to say!........
Oh, and "bump" to Karl!...........:rofl:
Glad Karl and I could help you out. I think he'd concure with me on your flame arrestor as the source of your flat spot. You can rememdy this two ways.......first, I had to go back through your post because I didn't know if you had the DI model, which you don't.
By changing the flame arrestor to the aftermarket type, you've allowed a greater air flow through the engine. This isn't necessarily bad. You can get a little extra horsepower this way. But you have to change out your pilot jets. Not to sure about your main jets since you say that once you get over that flat spot, she really goes!.......that's good.
The carb has three different working positions. First, the first few degrees the throttle plate opens, the low-speed screw is adjusted for idle speeds. Then, your next position is from those first few degrees to about 1/4, that's your pilot jet alone, then from there to almost wide open, your getting your fuel from the pilot and main jets. At WOT (wide open throttle), your fuel is basically completely through your main jet.
Here's something you can try if you don't want to put your old air induction system back on. Mark your set point on your low speed idle screw (so you can put it back if needed). Then, turn it just a bit to the open position. This will allow more fuel through the carbs at that slower speeds and may help get rid of that flat spot. If you notice a difference, open it a little more till you get it right.
One more thing, that big black box is designed the way it is so that it changes the direction of the air a couple times. For each time the air changes direction, the heavier water molecules drop out of the air and won't make it into the engine. You've eliminated that by the aftermarket flame arrestor. Also, if you are able to open your slow speed screw to take out that flat spot, then your running your engine a little richer in fuel which in turn means you need to have more oil from your oil injection pump delivered to keep the fuel/oil ratio in proper balance. I don't have to explain to you why, I'm sure you know that.
My personal opinion, put that ugly black box back on. You'll probably get longer engine life with it verses the pretty aftermarket type.
Sorry for the long post, sometimes, the extra information is needed to ensure you get a good understanding of what I'm trying to say!........
Oh, and "bump" to Karl!...........:rofl:
Last edited by a moderator:
- Status
