1989 Force 85 bogging down

[Grommett2k]

New here, so thanks in advance to all that provide help and info. I have a Force 85 on the back of 89 Bayliner Capri. Boat has sat for the winter so I spent the last couple of weeks getting new plugs in it and lubricating all the points. Also put new gas in it.

Got it out the first time yesterday and about 5 mins past the no wake zone boat dropped from just 30mph on full throttle to 10mph. Dropped back to neutral and seemed to be idling fine. When I accelerated it seemed to do the same thing, fine for the first couple of minutes then back to bogging down. Dropped back into neutral to see if the third time it would repeat and now it just go from idle to bogging down.

Took it out of the water, fule filter looks good, and plugs look good. Father in law recommended I use some decarb. Anyone have any other ideas on the first place to look? Also, I did replace a battery cable a few weeks back, could it be that?

 

[Grommett2k]

Re: 1989 Force 85 bogging down

I think I found a possible reason for my dilemna, or maybe even a new. I was given the engine a look over and I found a line that is disconnected. I believe it is part of the fuel recirculation system. The line is coming out of the manifold just below the bottom carb. On the end of the line is a brass fitting with threads that evidently means it should be screwed in somewhere. The threads look stripped a bit so that is most likely why it came out. I can not tell from the manual where this loose end needs to go. Anyone know? I am including some pics that will hopefully help.

 

[Grommett2k]

Re: 1989 Force 85 bogging down

 

[Frank Acampora]

Re: 1989 Force 85 bogging down

If that's the one I think it is, it goes from the bottom of the air box to the bottom of the manifold. Its purpose is to drain collected oil and gas from the air box. there is a metered hole in one of the fittings so unless the fitting is missing from the manifold, it will cause no problems. Take off the air box (6 screws into the carbs) and replace the fitting and hose. If it is stripped, just epoxy it back in.

What you describe--runs fine then bogs down ,put into idle then runs fine and bogs down again- sounds exactly like what a fuel delivery problem would do: When you start it, the fuel bowls are full and the engine runs fine. As you run it, the carbs run low on gas and the engine loses power. If you put it into neutral, It isn't using much gas and the fuel pump can catch up. Then as you power up, the carbs again run out of gas. You need to check the entire fuel system for restrictions and clogs, and be sure the fuel pump is performing correctly. Check the carbs for stuck floats. If the situation is getting worse, it means that something is clogging worse as time goes on or something is deteriorating (Like the fuel pump diaphragm) If you have a quick connect fuel fitting, remove the male fitting and check behind the ball check valve. This is an easy spot for clogs to form--especially if there is no strainer in the tank.

 

[Grommett2k]

Re: 1989 Force 85 bogging down

Thanks, that is it. I got the fitting on, and put a new clamp on the line. Started it up and it is idling. Will take it out tomorrow and see if it is still having the same problems running at full throttle. Thanks again!

 

[Grommett2k]

Re: 1989 Force 85 bogging down

OK, took it out yesterday and it ran better, but not best. It got up to speed but it still lurched every now and then though it did not bog down so much. Here is what was done before yesterday's run.

Disconnected line in recircualtion system was reconnected. New plugs. Decarb. Fuel pump rebuilt.

After getting it back home last night I went through all the fuel lines and checked for clogs and checked clamps. Went to store and bought new pump ball and line. New filter. And new quick connect. I also will be cleaning the carbs and I am thinking of just replacing all the fuel lines and clamps....figured it won't hurt.

Any other ideas on something I may be overlooking?

 

[gjm]

Re: 1989 Force 85 bogging down

My 1989 85HP always did the same. I had it in to shops many times. I took my carb off, lower one, it was spitting gas. I found holes in the float. I found a used one at a local marina for 10 bucks. That was it, now it runs and does not bog down.

 

[Grommett2k]

Re: 1989 Force 85 bogging down

I'm back. Got boat back out on the water after going through carbs and cleaning them out. Boat is running better, but still has a surging issue.

Boat gets up to between 15-20 mph and then it will surge intermittently. Like it wants to go faster. I thought maybe I had some bad gas so I ran it for a while and the surges started coming more frequently and lasting longer, but have not gone away.

I have pretty much gone through everything on the motor that has to do with fuel. I am now wondering if it is a gas quality issue, or maybe something in the tank itself? Maybe there is something in the motor I have overlooked?

 

[hgmatt]

Re: 1989 Force 85 bogging down

I think this might help. I've been having a similar problem on my 89 capri. When it was connected to the inboard fuel tank, which sat for years before I bought it, the gas had turned into varnish and began flaking off when I put a new tank of gas in. What I found was that the screen on the bottom of the tank was being blocked by these flakes at full throttle & less than 1/2 tank of gas. Sometimes the engine would bog down completely other times it would have intermittent surges.

As a temporary solution (will be pulling the tank this winter to clean it out), I cleaned it the best I could using a phosporic acid solution (etches metal & dissolves varnish). I used a concentration of 1 gallon phosporic acid to 20 gallons of water, per the instructions, drove the boat around on the trailer looking for potholes & other bumps. After that I let it sit for several hours and then pulled out as much of the solution as possible. Then I mixed up a solution of baking soda and water and tried to get out as much of the acid as possible, then using a hose I flushed the tank for about an hour.

Now, this didn't work as well as I would have liked, so removed the screen at the bottom of the intake, installed an inline fuel filter in addition to the fuel filter & fuel water seperator on the motor. I haven't taken it out on the lake since I pulled the screen, but it seemed to work pretty well on the muffs and in a tank. I would throttle up to about 2.2k rpm. I'll be out on the lake by the end of the day, so this might be a good temporary solution for you, if your having a tank problem. If someone else who has more experience disagrees, I would follow their advice. We'll see by the end of this weekend how it turned out. Oh, a great way to determine if you're having a tank problem would be to attach a portable tank (can get one at Walmart) and see how the Force performs with this tank.

 

[yfz450guy]

Re: 1989 Force 85 bogging down

well?
what is the outcome? we want to know.

 

[hgmatt]

Re: 1989 Force 85 bogging down

It worked really well, until I had about half a tank left. Then the floating crap in my tank was low enough to clog the intake after all. I guess the crap in there is bigger than the diameter of my intake. I was thinking that this stuff was smaller than the diameter of my intake, but larger than the screen's size. I guess there is only one solution left for me, pulling the tank and cleaning it.