85 force o/b 85 dies off under throttle

[CATFISH KING]

last few runs last season my 1st boat, '85 bayliner capri cuddy force 85 started dying out under WOT, pulled back on throttle, picked up power, and began to die back off. is this a carb cleaning/rebuild issue or coils? i'm new to boating (last year) and i got this boat for a steal. i replaced the starter, fuel tanks, lines, bulb and filter. she was running fine all season til the last couple of runs... anyone?

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

also, with more than 2 people in the boat, she won't break plane unless the 3rd person sits in the cuddy for a minute or 2... then she's fine.. is this a prop or how far down the engine is in the water?

 

[Frank Acampora]

Re: 85 force o/b 85 dies off under throttle

Could be a bad fuel pump needing a new diaphragm--sounds like it is running out of fuel at full throttle. Could also be clogged inlet needles or stuck floats in the carbs or a partial clog in the fuel lines or quick connect fittings. Could also be a partial clog in the in-tank strainer. Before doing the carbs, try everything else first.

As far as planing, could be underpowered, engine might not be producing full power, or you may be incorrectly propped. Engine needs to turn 4500-5500 RPM at full throttle to make full power. If you don't have a tach, buy one It will be the most useful gauge you have on the boat. OR---you may simply need a couple of tabs. Look in the general boating section for posts on Smart Tabs. The guys there mostly swear by them, and they are not too expensive.

 

[cjac2879]

Re: 85 force o/b 85 dies off under throttle

This is a little off topic, but how did you go about replacing the fuel tank... I hae an 86 bayliner capri cuddy, and was interested in doing this, but was told you have to remove the whole floor??

 

[john from md]

Re: 85 force o/b 85 dies off under throttle

We need a little more info to properly troubleshoot your problem. What is your normal WOT RPM? Do you have hydraulic or manual trim? Is the anti cavition plate on the engine even with the keel of the boat?

As to the engine running poorly, Frank covered most of the areas. There is one other to check. When the engine dies, is the bulb hard or soft? Try pumping it as the engine is dying and see if you can keep it running. If you can, the check valves in your fuel pump may be sticking. There are three of them and the alcohol in today's gasoline causes the valve to swell and stick.

John

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

i have 2 external plastic tanks that sit on the floor just in front of the outboard between the transom and engine...

 

[drin1932]

Re: 85 force o/b 85 dies off under throttle

On any force engine i would start by compression testing all cylinders with any kind of running issue.

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

from what i recall, the bulb was fairly soft, i dont have a tach, so dont know the RPM's.. also the overheat alarm sounds when the boat is out of the water running on muffs.. can i use a plastic 55 gallon barrel to drop the prop in to help circulate water? getting to the lake and working on it is a hassell, and where is the best place to get fix it parts (online or otherwise)?

 

[john from md]

Re: 85 force o/b 85 dies off under throttle

You can only run the engine in gear at idle in a small container. Anything higher causes cavitation and throws water all over the place. For accurate troubleshooting you will have to be on the water.

If you can keep the engine running by slowly pumping the ball, the check valves in the fuel pump are bad. They cost $5 but you have to be a good mechanic to change them.

Parts can be obtained on line from Iboats, mercruiserparts, crowley marine and a host of others. Be advised, sometimes the seller has to shop around to find the parts so you may not get them as fast as you think. These are old engines after all.

John

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

cool. thanks fot the info. guess i'll check compression first and go from there.

 

[geeco1]

Re: 85 force o/b 85 dies off under throttle

One more thing to look at.... this happened to me and I feel stupid, but it only took me a few minutes to figure out.... make sure that the vent screw on your gas tanks are open.

I have 2 tanks and I had to switch tanks while on the water. I forgot to open the vent. The engine would start and run, but when trying to get going, it would dog-down and die. I thought for sure that I had engine problems, but the I realized the vent was closed. No problems after that

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

no, i found that out early on in the season. Am very sure everytime i swap tanks to be sure it's open. got the battery on charge now, gonna give her a good wash down, fluid change, wax, and put her in the next weekend or so. be sure ya'll will see some more posts from me. there is a dude down here that comes to you and works on boats, but i wanted to exhaust most of the "simple stuff" myself. carb cleaning, maybe rebuilding, much past that, i'm a goner! thanks to all...

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

ok. I checked compression... 128, 125, 128.. so thats seems fine..i replaced the plugs that were in there, champion L18V for the L76V's. replaced the fuel pump diaphram and gasket, spayed a little carb cleaner down the throats, changed the LU oil, lubed all linkages and fittings and charged the battery for a few days and..... she fired right up.. cold start!! Now I just have to get her out on the lake in the next few days to get her up to speed to see if that fixed my bogging down issue.. thanks for all the help. hopefully that got it right. a question about transporting with the engine up. i don't have trim/tilt. could someone post a pic showing the best way to make something to secure the engine in the "up" position for transport? I havn't been doing it the right way i know, but we only have to drive about 20 minutes to our lake, so not like it's going far, but i don't want to take any chances... thanks again for everyone's help.

 

[john from md]

Re: 85 force o/b 85 dies off under throttle

Do you have a trailering bracket? It looks like a round piece of metal in the shape of a C of sorts with a hole on each of the side legs.

John

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

is it on the boat transom, or on the trailer?

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

if i can get pics to load, this is what i got... i can see where something once was on the left side of the transom.. but it's gone now. maybe thats what you are talking about...

 

[john from md]

Re: 85 force o/b 85 dies off under throttle

The trailering bracket that came with the boat was a 1/2 inch round bar bent in the shape of a { with holes at each end. You would mount it to your engine mount with the engine in the position that you have it with the 2x4. It was held in place with the pin that positions your engine tilt. Then you would lower the engine on to it and lock it in place with the engine tilt lock.

Since you don't have one, I suggest you buy one of the aftermarket trailering braces that they sell that attach to your trailer. These are usually made of aluminum and attach to the trailer and then you attach it to your engine and they keep the engine from placing a strain on the transom when trailering.

Go to Westmarine's web site and search for "transom saver." They sell a few different types. The dual mount one costs about $45 and would work for your set up.

John

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

i have seen them at walmart, but they say for use with engines with trim/tilt only... can i use one of theses?

 

[CATFISH KING]

Re: 85 force o/b 85 dies off under throttle

another dumb question.. in the first picture, the spring loaded contraption near the bilge drain hole, is that a trolling motor mount? if it is, mine my be missing something.. it will fold down, but not lock in place... if its not a mount, what the heck is it?

 

[john from md]

Re: 85 force o/b 85 dies off under throttle

I don't know if the Walmart unit will work or not. I suggest that you ask the question about transom savers on the general maintenance (not engine specific) board.

The folded thing on the side is a mount for a gasoline trolling motor. Its pretty rusted out so I would chuck it.

By the way, your compression, while pretty even is low. Your engine should have numbers near 150 psi. The reason is probably carbon on the rings. You need to do a good decarb, maybe even a double decarb. It will improve your performance and decrease your fuel burn.

John