1987 85 hp Force No Power Dies at idle.

[bmayhan]

I have a 85 hp Force that will idle for about 2 minutes then speed up a little and die at an idle. If I try to restart it will just crank like its out of fuel. If I pump the primer bulb a couple times and try to start it will fire right up and run for another couple min. Out on the water it has no power at all at full throttle. I replaced the hose, filter and primer bulb from the tank to the motor. Checked and cleaned the screen on the fuel pump. I just had the boat in the shop and they checked the ignition system and replaced the trigger and all the plugs.

 

[pnwboat]

Re: 1987 85 hp Force No Power Dies at idle.

Sounds like a bad fuel pump diaphragm.

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Would that also cause it to use more fuel? We went through about 9 gal in 3.5 hrs on the lake, most of which was spent running out from the shore and back to shore while trying to figure out what was going on with it.

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

Force engines are not known for being economical to operate.

Is the bulb soft when the engine shuts off?

Can you keep it running by having someone pump the bulb?

Was the fuel pump changed recently?

Get back to us.

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

The primer bulb is soft when it dies. I can keep it running if I pump the bulb once about every minute or so. I have not changed the fuel pump since I have owned the boat, (3 years)

Thanks for the replies.

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

The problem is that the three checkvalves in the pump are sticking. This is caused by the alcohol in today's gasoline reacting with older check valve material. They cost $5 each at www.crowleymarine.com or www.boats.net.
A fuel pump diaphram and gasket will cost about $6 from the same places.

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Thanks I will get some parts ordered.

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Update... I ordered parts for my fuel pump this afternoon, so I thought i would take it off and see what I was up against. After I got it off I thought I head it rattle, so I opened it up and found that the middle check valve and 2 little screws were completely out and rattling around. I put the check valve and screws back in place and put everything back together. Started the motor on muffs, it fired right up and idled for a good 10 minutes. It has never idled that smooth. I am going to put new check valves in when i get them but I can't wait to test it on the water now. What would cause those screws to come loose and let that check valve move out of place?

 

[pnwboat]

Re: 1987 85 hp Force No Power Dies at idle.

Probably someone else changed the diaphragm in the past and was messing with the check valve and forgot to tighten them up.

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

OK guys I have another update. I got all the parts for my fuel pump installed. Ran it on muffs in the driveway sounded good, so we took it to the lake and put it on the water. It ran the same as before, just no real snap or power. It did idle better than before but no power. We brought it back and had the local auto mechanic work on the carbs, he said the needle in one carb was not seating correctly so he fixed it. We took it down to the lake today with high hopes but were dissappointed when it ran sluggish still. It sounds smooth when running. Anyone have any ideas?

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

Ok, it idles better but no power. Is that during a hole shot or at WOT? What is your rpm at idle and at WOT? What speed are you getting out of the boat? What size prop is on the boat.

We need you to tell us the exact sequence of events since we weren't riding with you.

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Both the hole shot and WOT are sluggish. Its on a 18ft Capri, I have tried 2 props, one is a 13 1/2 X 15 and the other is a 19 pitch. The boat will run 20 mph if I trim up a little and give it awhile to get there. Just my wife and I in the boat. I am not sure what rpms I am getting, I am doing some research on how to get a tach installed on the motor tonight. Thanks

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

The cheapest tach to install is called a "tinytach". You can google them and find out about it. It is a small digital tach but it is fine for determining the health of your engine.

My 16ft Capri will do 43 with me alone in the boat with my fishing gear and 18 gals of gas. You definitely have a problem.

Are you still using more gas than normal? Is it smoking alot and does the lake water look like you are dropping oil in it?

Have you tried pulling a plug wire off at a time to see if one or more does not affect engine operation?

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Thanks for the tip on the tach. If i pull off the plug wire on any of the three cylinders the motor will die. The water did seem more cloudy behind the motor at the lake the other day. We noticed that but I guess did not put alot of thought in to it. Wow 43mph I would just like to see mine do 35mph.

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

Well, that shows that all three are working.

Another power robber is incorrect timing. If your timing is not advanced properly, it will not put out full power. Your timing should be set at 30degrees cranking or 32 running at WOT.

There is one thing I hesitate to bring up. Have you ever had your boat weighed? The reason I ask, is that the foam and wood can get soaked and add lots of pounds to a boat.

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Thanks John, I will take it across the scale next time I have it hooked on the pick up. Do you have any idea of how much it should weigh? I will try to check the timing this week.

 

[raekmike]

Re: 1987 85 hp Force No Power Dies at idle.

Check your boat registration. your weight should be listed on there..then guestimate your engine weight and gas and add it up. should get ya close..

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

I can't find an 1987 1800 Capri listed in the NADA books. Are you positive it is an 1800?

John

 

[bmayhan]

Re: 1987 85 hp Force No Power Dies at idle.

Just double checked the hull Id it is a 1989 instead of a 87

 

[john from md]

Re: 1987 85 hp Force No Power Dies at idle.

I still can't find an 1800 Capri in NADA manual. The weight of a 1700 is 1475 and the weight of a 1900 is 1655.

Your boat should be somewhere in there. If you have a single axel trailer, add about 400 pounds.

Regards,

John