1989 Force 85 stalls at full throttle

[john from md]

Re: 1989 Force 85 stalls at full throttle

I don't know as I haven't tried using 1/4 inch line. The earlier engines use 5/16 and I currently use 3/8 USCG fireproof alcohol resistant like the newer engines use.

Fuel line is relatively cheap, so I would change it out.

john

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

John, the inlet to my fuel pump is for a 1/4" line. I assume this is the factory pump. Can I put a 5/16" line on a 1/4" fuel pump barb, and would it even make a difference, considering the fuel pump can only take in so much, regardless of how big the line? Thanks.

 

[john from md]

Re: 1989 Force 85 stalls at full throttle

Use a good quality stainless worm clamp and you will have no problem installing 5/16 line. As to whether it will make a difference, I really don't know.

John

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

Here's where I'm at... I can't figure it out. So far I've put in brand new fuel line & primer bulb. Installed new diaphragm and check valves in the fuel pump. Took apart, cleaned and rebuilt the carbs. Reed valves are good.

Took the boat out yesterday and it took a good 45 seconds to plane off, but it eventually did, ran at a steady 21 MPH for about 3-4 minutes then started to lose power. Dropped it into neutral and the motor kept running. When I throttled up again, the boat would not go faster than 8 MPH at WOT. Dropped it into neutral and took off the fuel line to check the screen. It was clean. Put it back in and throttled up again. This time it planed off (a little better than the first time) and I ran it back to the dock at WOT with no problems (5-6 minutes). WOT was about 25-26 MPH. Slower than it should be but we were running into the wind and had 2 adults (combined 420 lbs). I was happy that I was able to run it back to the dock at WOT without losing power but it's still not planing off very well, and loses power often.

Any ideas? I'm almost positive it's a fuel delivery issue, but just can't pinpoint it. Thanks.

 

[Frank Acampora]

Re: 1989 Force 85 stalls at full throttle

Ahhhh! Do you have a quick-connect fitting at the tank? If so, remove the male fitting and clean out behind the check ball. Crap collects around the internal spring and either partially or fully clogs the fitting. Partial clog ---fine running until the engine requires more gas that the fitting can pass.

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

I do have a quick connect fitting at the tank! And it is old because i took it off of another temp tank. Funny thing is... I already picked up a new barb so I can take off the quick connect and hook the hose directly to the tank and it slipped my mind when I went out yesterday. I'll give that a try. That just might do the trick. Will let you know. Thanks!

 

[john from md]

Re: 1989 Force 85 stalls at full throttle

Frank,

Good to "see" you are back.

Thimsllib

Have you checked your timing and compression? What size prop and what size boat?

John

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

Haven't checked timing or compression to this point. Would need someone to do that for me as I don't have the equipment.

The boat is a 17' Capri. Prop looks original and a little banged up. My guess is it is a 17" pitch since the only marking on it is a 17 stamped into the side.

 

[john from md]

Re: 1989 Force 85 stalls at full throttle

You should see a lot more speed in that boat, even with a 17 pitch prop. My 16ft Capri with an 85hp will pull me and my fishing gear and 21 gal of gas at 40 MPH (GPS) on an average day, on a calm day I can get 45 MPH.

Have you ever had your boat weighed? You might want to take it to a scale and see how much the whole thing weighs and then subtract about 400 for the trailer and 250 for the engine. You can compare this to the NACA weight charts and see if it is water logged.

There has to be a reason it is running slow.

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

Thanks John. I agree that it's probably water logged. The floor is shot and has the original carpet. This coming fall/spring I am going to rip out the floor and replace the floatation foam. Hopefully that'll git'er goin. This summer has been nothing but tinkering and test runs.

I replaced the quick disconnect with a new barb. Probably won't get out until Sunday. I'll post my results. Really hoping that will do the trick.

 

[thimsllib]

Re: 1989 Force 85 stalls at full throttle

So, I think I have water in the fuel tank. Took the boat out this morning and everything was going fine. Boat was going about 28 MPH at WOT (I know that's slow, but consistent for this boat as of now). Backed it down and cruised at 21 MPH for a good 15 minutes. Then all of a sudden the motor bogged down. Didn't stall but i dropped it into neutral and it sounded like it was misfiring on 1 cylinder. I turned the motor off and pulled the screen in the fuel line just to make sure no debris. It was clean. Started the boat back up and the cylinder was no longer misfiring. Took a little while to Plane off then cruised back at 21-23 MPH. again, hit 28 MPH at WOT.

Does that sound like the motor took a gulp of water? Everything else seemed to be working great. I know that a decent amount of water got in the tank at one point. I've been using dry gas, but I guess that might not be a cure all. What's the best way to get water out of a fuel tank?

 

[mort kent]

Re: 1989 Force 85 stalls at full throttle

I have the same problem with my 50 hp, I have changed everything from the tank to the carb, no results. It stall when you give it throttle. mort