Injector Upgrade on 99 w/ Monsoon

[Sethro]

Any chance @Engine Nut could comment on the different injector output 24 vs 27?  I think we'd all value your input.

[gregy]

I pulled a few plugs and they looked pretty normal.   I checked the oil today and it did not seem to have any signs of gas.  I am having some fuel smell at idle again though.  I put a fuel gauge and checked it at idle and it went right to around 40psi.  The gauge was jumping around +/- 3 psi.  Should it be constant? 

Edited March 26, 2017 by gregy

[Shastasurf]

https://www.bakesonline.com/images/MediaLibrary/Indmar_96-06FuelpsiRef.pdf

The pressure remains constant on my cheap gauge.  

Edited March 26, 2017 by Shastasurf

[MadMan]

On ‎3‎/‎25‎/‎2017 at 7:44 PM, gregy said:

I pulled a few plugs and they looked pretty normal.   I checked the oil today and it did not seem to have any signs of gas.  I am having some fuel smell at idle again though.  I put a fuel gauge and checked it at idle and it went right to around 40psi.  The gauge was jumping around +/- 3 psi.  Should it be constant? 

Your fuel pressure regulator is referenced to the pressure (vacuum) present in the intake manifold, while your fuel pressure gauge is referenced to atmospheric pressure.  It will fluctuate with manifold vacuum at idle.  This is also the reason the fuel pressure increases at wide open throttle (WOT), because during this condition the manifold pressure equals atmospheric pressure (0 vacuum). The idea behind this arrangement is to keep a constant pressure across the fuel injectors.  On later engines the regulator is reference to atmospheric pressure.

Edited March 28, 2017 by MadMan

[Engine Nut]

On ‎3‎/‎25‎/‎2017 at 6:44 PM, Sethro said:

Any chance @Engine Nut could comment on the different injector output 24 vs 27?  I think we'd all value your input.

I would not personally be comfortable going to an injector that would reduce the amount of fuel. The leaner operation may make the engine run better in certain RPM ranges but generally speaking fat fuel is safer and those injectors were chosen for a reason.

Larry

[Shastasurf]

So I just checked the number on my injectors in my 1996 320 monsoon.  This is number on my injector 17095004.  I pretty sure they are rated at 24#.  https://www.injectorrx.com/rochester-fuel-injectors/

Is your injector different than mine? How did you know yours was 27#?  I want to replace mine but don't want to be lean!

[gregy]

Mine are 17121068 which are according to your chart 24 lb and from what I found on the internet it backs that up.   So not sure who told me they were 27lb, at this point I can't remember.   Boats still running good and plugs don't show any signs of lean or rich fuel mixture. 

[gregy]

These injectors have been in use for a while.  I'm going to call it a success.  No gas in oil and plugs still look just look they should.  The one time that we had some fuel small it was pretty cold that day.  I thinking it had something to do with the open loop system.