120 Horse Force loss of power

[gregChapman]

I am new to this forum and appreciate any help. i have a 1990 Force 120 horsepower engine.

I was boating yesterday when the boat lost power. was pulling my daugher going about 20 miles per hour. it was like someone cut off the gas. Engine started after that (somewhat difficult to keep it running) but could not get it to power back up...engine was bogged down. Engine has had difficulty lately when putting it in gear.

After reading some of the posts, seems like it could be a coil issue. any other thoughts?

thanks.

 

[john from md]

Re: 120 Horse Force loss of power

Before you go jumping to coils, you need to do some troubleshooting. BTW, coils don't go bad often.

Do you have an inboard or external tank? What kind of maintenance have you done to the boat lately? How long have you owned it? What is your normal WOT speed and RPM? Do you have any filters in your fuel system?
Have you ever changed your fuel pump or cleaned your carbs?

Give us some additional info and we will try to assist.

John

 

[pnwboat]

Re: 120 Horse Force loss of power

Can't assume anything without doing some basic checks.

1. Compression - to verify pistons & rings are OK.
2. Fuel - need to check fuel pump for bad diaphragm.
3. Carbs - does primer bulb get hard after 4 or 5 squeezes. If so, needle valve in carbs should be OK.
4. Fuel tank vent - Is it open and not plugged.
5. Check for spark on all 4 cylinders.
6. If missing or weak spark, swap coils around to see if problem moves.

 

[gregChapman]

Re: 120 Horse Force loss of power

Thanks.


Do you have an inboard or external tank? I have an internal tank (i believe it is 18 gallons)

What kind of maintenance have you done to the boat lately? I haven't done anything lately...i had the plugs done last year and i have had a mechanic winterize the engine each year.

How long have you owned it? I have owned the boat for 4 years. bought it off the original owner who claimed it had 400 or so hours. hard to tell. did have the compression tested last year and the mechanic said it was in good shape from that stad point

What is your normal WOT speed and RPM? It is a tubing maching for my kids...generally never go over 30 mph and the RPM sits aroudn 3,000 - 4,000 RPM

Do you have any filters in your fuel system? Honestly don't know. when it first happened, it felt to me like something was in the gas...the Bogging feeling was enough to pull it out of the water. need to look at it again this weekend.

Have you ever changed your fuel pump or cleaned your carbs? I have not changed my fuel pump...don't know about Carbs...could get that done. it was a pretty significant loss of power and then the boat was difficult to start so i assumed it was a big problem.

Thanks for your help!

 

[john from md]

Re: 120 Horse Force loss of power

With the Alcohol in the gasoline these days, it is causing many problems in boat engines. Especially those with inboard tanks. The ethanol causes delamination of fiberglass, corrosion of metal and also allows stuff to grow in the tank if the enthanol separates from the gasoline.

Google ethanol and boats and see what you come up with.

Anyway, you need to check your tank, which is hard to do, to see if any garbage is in it. Also, under the cowl you will find the fuel line going into the fuel pump. The entry point is a screen filter. You need to unscrew it and see if it is clogged with junk. If so, the entire fuel system needs a good clean out. That means tank, carbs etc.

Let me know what you find.

John

 

[gregChapman]

Re: 120 Horse Force loss of power

will do...thank you for your help. will be out there this weekend and have some time to mess around. does seem logical that it is gas related...such a sudden loss of power with nothing leading up to it. In all my years of boating, i have never experienced anything like that.