96 H200 58FCPNCS poor idle and no power

[kodyman84]

Back again guys. The boat no longer overheats but now I have another problem.

Seems to have a high idle of about 1000 rpm when warm. Also a rough idle after revving. I know the throttle cable is some what sticky because I can close the throttle by hand but it still will idle around 1000.

When under way and about 3000 rpm the boat isn’t going anywhere near as fast as it should be. Doesn’t hesitate or anything but definite lack of power.

 

[Bondo]

Ayuh,..... Sounds like the carb could use a rebuild,....

Does the throttle cable push slightly against the idle screw at no throttle,..??

 

[kodyman84]

Should have mentioned that it is fuel injected

 

[kodyman84]

Okay boat buddies. Did some more digging tonight as to what is going on. I started off by pulling the throttle cable off from the throttle body and then starting the boat. Same high indicated idle of 1000 and change. So I don’t think the cable is holding it open. However the cable is still sticky feeling IMO. So I might change it at some point. When I had it running I snapped the throttle open a few times, when it would idle down the rpm would dip to 600-700 and then return to 1000 and change. But I could tell it was struggling, tried it a few more times and actually killed the engine. So for sure got something going on. (Like I didn’t already know that)

next thing I did was pull the plugs for inspection. I wasn’t too impressed with what I found. All of them looked pretty bad, and none were properly gapped. They ranged from .030 to .040! Factory spec is .042 to .046 so a new set of plugs is certainly in order. Going to do new wires as well just to
be safe. I’m having a hard time sourcing a set though, all of them seem to be sold separately. Also thinking of a new cap and rotor.

While I have the plugs out I figured it would be a good time to run a compression test. Everything looking great there. All cylinders ranged from 135-140 psi on a dry test. So that is a relief considering all the problems I’ve had thus far with this boat.

For being 22 years old and only 170 hours, she’s done a whole lot of sitting in her time! I should have expected this when I bought it.

 

[kodyman84]

At it again this afternoon. More answers and more questions.
Bought a cheap digital wireless tach to confirm my rpm, and low and behold the gauge is wrong, it reads 1000ish and the digital tach reads 610ish. So that’s a good tidbit to know.

I also checked the timing and it appears to be on, 5* btdc.

I grabbed a set of motorcradt plugs from auto store while I wait on my ngk 3263 plugs in the mail. Swapped those out and no noticeable change, when I snap the throttle open and let it go the rpm drops real low and almost stalls. I also pulled out the DMM and check the resistance on my plug wires, all between 10-17k depending on length, shorter were less and longer more...normal.

Pulled off the flame arrestor and it was dirtyish looking, gave it a cleaning with some carb cleaner. waiting for it to dry.

pulled the iac valve off, the thing was squeaky clean inside! No sign of carbon build up.

opened and closed the butterfly valve on throttle body by hand, smooth as could be, again no carbon buildup.


What else should I be looking at?

 

[kodyman84]

Changed the fuel filter just now. Also took my gas can down and got a few gallons of some fresh supreme. Hooked that up and ran it. No noticeable difference.

When I open the throttle and rev it a few thousand rpm it returns to idle just fine. It’s when I only give it a small rev of maybe 600 or 700 that it seems to sputter and hunt a little when it returns to idle.

Also I have a four blade prop and 1:51 gears on the drive. Don’t know will this contribute to the lack of power ?

 

[kodyman84]

Drum roll please....

Bad ignition coil. I pulled it off to bench test it and the primary circuit resistance is out of range. Supposed to be .39-.42 ohms and mine read 1.2 ohms. The connector to the coil was also cheesed up pretty good. Take a look at the before and after pics. Cleaned it up nice with some electronics cleaner spray.

Hopefully by next weekend I’ll know if this completely resolved my issue.

Btw...feel like I’ve been running a one man race on this posting. Everyone must be out enjoying their boats, as I should be

 

[kodyman84]

Well ****

i guess my DMM isn’t that accurate. My ignition coil was/is just fine.

Im now onto a fuel related solution. Or so I hope. Check the fuel pressure at the reservoir (low pressure pump) it was 5 psi which is within spec. Then checked high pressure on the fuel rail and it came in low. Only read 32 psi, spec is between 36-42 psi. Now for the interesting part, I was trying to figure out if it is my pressure regulator, so I pulled off the vacuum hose on top of the regulator which also makes the fuel pressure jump up by roughly 8 psi. And low and behold my idle smoothed out and she started purring like a kitten!! So my issue is most certainly fuel related and not on the ignition side like i thought.

But is it my high pressure pump or the pressure regulator? What can I do to figure it out?

 

[further]

Did you pull out the fuel pressure regulator? Had a similar issue and the screen was clogged with a bunch of crap... There's actually a service bulletin for those - to remove the screen and replace with an E-clip due to issues with the screens restricting flow.

 

[kodyman84]

I was looking at the pressure regulator last night, it’s going to be a bugger either way I go about it. Service manual says to pull off the throttle body, plenum and fuel rail to access the regulator. It is in a tight spot on the rail, almost half under the plenum and the three Allen screws that hold it to the rail are pointed down towards the bilge.

But I’m going to give it a shot, and if I can’t get it off then I’ll go ahead and remove the rest of the upper intake.

Going to also try and run the pressure test again tonight off of my 3 gallon tank, just to confirm it’s nothing on my fuel tank side.