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Need some accel pump help!!!! Login/Join 
posted
I have an 2001 XR1800 Yamaha boat with the twin GP1200R engines in it.

Here is my setup:

D plate installed
Stock airbox
Tamper caps removed: 1 1/2 highs, 1 1/8 lows

I am having horrible acceleration problems up to the dreaded 4000 rpm zone. I can't seem to get her past them . I thought it may be bad fuel / filters and changed the filters, but no dice.

Another jetboater advised removing/disabling or maybe adjusting the accel pump. I use the boat for waterskiing so hole shot is pretty important. If I turn the adjustment screw in, does that provide less fuel or more??

I really dont want to rejet if I don't have to.
 
Posts: 33 | Location: Davenport, IA | Registered: June 16, 2003Reply With QuoteReport This Post
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Turning the high or low adjustment screws IN will lessen the fuel. If your boat acted fine before now, I can't see how the accelerator pumps are to blame. I'd look elsewhere for the problem. If the problem just popped up since the D plate installation, you may need to open up your screws. Read the plugs to be sure.
 
Posts: 2002 | Location: Houston | Registered: March 21, 2003Reply With QuoteReport This Post
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The boat has had this problem since it was new and the dealer is clueless. His best attempt was to increase the idle speed to 1600-1700rpm.

Even if I disable the accel pump, the port engine dies when I punch it. Am I too rich or is my waterbox filling up and the backpressure too high. Could this be a powervalve problem?
 
Posts: 33 | Location: Davenport, IA | Registered: June 16, 2003Reply With QuoteReport This Post
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It honestly sounds like an acc pump problem. Can you see the pumps squirt if you operate the throttle while the engine is off? How do the plugs read?
 
Posts: 2002 | Location: Houston | Registered: March 21, 2003Reply With QuoteReport This Post
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I can't see the squirt but I can hear it when I rotate the throttle wheel.

I haven't done a low speed plug chop yet. Is that what I need to do? Idle for 4-5 mins and then chop it and pull them? If so, am I still looking for a medium brown color?

Also, after I set the idle down to 1350-1400, after a run of over 4000rpm for a few mins, the engines idle at 1600 again. It keeps creeping up on idle.
 
Posts: 33 | Location: Davenport, IA | Registered: June 16, 2003Reply With QuoteReport This Post
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