1989 Force 85hp - Idles great at home, won't run at the lake

[Jlesinski]

Hello,

I have been having a heck of a time with my 1989 Force 85hp. I had a couple recent posts where I believe I resolved some electrical issues as the magnet came off the flywheel and the trigger wires were rubbed. I glued that back in, replaced the trigger and checked timing for good measure. I have great spark now on a gap tester and I can turn the key while it is on a water troth and it starts right up every time. No choke is needed.

Now, I had also cleaned up the carbs and changed the gear oil and decided to take it to the lake for a test. Sure enough it would barely run under load. It would start and idle but as soon as I put it in gear it would want to stall. I eventually could get it to move but if I gave it any throttle it would bog and die.

I had followed Franks Carb lync and sync guide and set the idle jets to 1 turn out thinking I would need to adjust at the lake, but with it running so poorly I only turned it 1/4 in or out and it just didn't seem to make much difference and I decided to pack up and troubleshoot at home (I don't need pieces in the water) and I know not to go less than 3/4 turns in or risk leaning out.

I get back home and double check spark, all is good. I checked the fuel pump diaphram that I replaced last year and that was intact.

Next I pulled the carbs off to make sure the floats were moving. They sit at horizontal upside down and I can't blow through them. They seem to be operating properly. I plan to clean them up again and blow them out and reinstall.

So... do I need to take the idle adjustment screws out much further? Is it possible that the idle screws would be at like 2 or more? Is there something else I should be looking at? Sorry I know there is a lot going on here. Oh, and I put in fresh gas/oil at 50:1 before I went out.

It seems like a fuel issue to me since I believe I resolved the electrical issue.

 

[Bomber81]

Are you sure you have spark at all cylinders?

 

[Jlesinski]

Yes I have tested since getting home. I cleaned the carbs and reinstalled them tonight. Then sprayed every fitting and all around the carbs with wd40 while running to see if it changed the idle. It seemed to stay the same and didn't affect idle at all.

The idle air screws are set to 1 turn out and I went through the link and sync procedure again to be sure. I also checked the timing again and it was dead on 28 degrees while cranking at wide open throttle. I changed it to 29 degrees to see if that helped at all. I can put it in forward in water trough and it works fine, but I am concerned that it is not going to run at the lake again...

I have attached a video of it running so you can see how it is. It seems a little smoky to me but it's indoors so probably normal.

Here's a quick video of it running:

https://www.youtube.com/watch?v=StAHqumrLlY

Thanks!
Jim

 

[jerryjerry05]

They're not idle air screws.
They're air/fuel mix screws and aren't used to set the idle.
The idle is set using the screw on the bottom of the tower shaft.
The 3 screws set the amount of air/fuel at idle and just beyond idle.
The factory recommended to set at 1 turn out and leave them there.


Do the spray with starting fluid, not WD.
Starting fluid's flash point will make the test work better.

What's the rpm's at idle? 800 in gear at idle.

Try running with the cover off? Might be choking itself out from an exhaust leak??

All the smoke is from the tinkering trying to get it to run.
Continual starting and running at slow speeds loads it up with excess
fuel and oil. Once it's running some smoke will go away.

 

[Jlesinski]

Thanks Jerry. I did mean air/fuel mix. Those are what I am talking about. They are set to 1 turn out each.

I had to run out and pick up some starting fluid. I sprayed the hoses and carbs down. I didn't seem to have any issues other than if I got close to the air intake cover for the carb. That caused the idle to go down, which is not what I would expect? I verified by spraying a little directly into the intake cover and it did indeed cause the idle to drop. Maybe that's normal?

The boat doesn't have built in tachometer. I am going to borrow a tach from someone today and see if I can get that hooked.

 

[jerryjerry05]

They sell an item: called a Tiny Tach and other aftermarket tachs.
About 20$ just hook to the plug wire.

Make sure the one you buy has replaceable batteries.

 

[The Force power]

Just make sure to keep the lead from the tiny-tach. away from the other ignition-cables; it will pick up a signal from them & trow-off your readings

 

[Jlesinski]

I ended up buying a tiny tach and taking the boat out this weekend after having taking the carbs apart and cleaning them. We had zero issues. The boat started up, ran like a champ and kept starting the whole time.

I did buy a tiny tach and it showed my RPMs were are about 1000 RPMs in neutral and a little less in gear. I adjusted down to 800 rpms in gear and it runs OK still but it is a little harder to start and requires that I pull the throttle and move forward while starting even while warm.

I'd prefer to keep the idle a little higher so it starts right up so I may adjust up a little. The tiny tach did throw some odd numbers a couple times so I know what you mean about keeping away from other wires.

I think my whole issue was just a little bit of stuff in the carbs still so the cleaning took care of it.