85 HP US Marine, Force Outboard Not Getting On Plane

[buffalosmallengine]

This thing is kicking my behind. Any help would be greatly appreciated and thank you in advance. Ok here we go. We have a 85 HP US Maine Outboard on a I believe it is a 17 foot Capi open bow boat that will not get up on plane and bogs out at full throttle with a load. Idles fine. Engine compression is a little over 100 psi per cylinder, new stator, new fuel pump diaphram and gasket, carbs have been rebuilt & new plugs. Tested timing and it is advancing. Tested spark when under load with air gap checker and spark is blue on all three cylinders. Pump ball is staying fairly hard for the most part. Had the pitch of the prop checked as was told that it is ok. When the engine bogs down there is still blue spark on each cylinder. Also tried moving pin up and down to adjust engine position. The only other thing that we notcied is that the underneath of the hull has been patched from bow to stern and every time the boat is removed from the water, we pull the plug and I would say about 10 gallons of water comes out. Any ideas? Please Help !!!

 

[MikDee]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Welcome to the forum, hows your link & synch, is it set? next are the carbs opening all the way? finally, is the timing set right?

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Hi Mike and thank you for the response. I think that I have the carbs all adjusted properly. They all seem to open the same when the throttle is engaged and the advance arm moves as the throttle is increased. When I look at the butterflys when the throttle is engaged all the way, they are perfectly horizontal. You think it may be timing? Is it usually to far retarded or advanced when this happens? How would I go about checking it at high spped? What is the proper method for link & sync on these engines? I have all three floats in each carb adjusted to when they are upside down the float is level. Is there a possibility that you may be able to help me with a start point and what to check? Thank you in advance Mike and again I appreciate you taking the time out to help as this boat is making me age.

 

[maxum247]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

This thing is kicking my behind. Any help would be greatly appreciated and thank you in advance. Ok here we go. We have a 85 HP US Maine Outboard on a I believe it is a 17 foot Capi open bow boat that will not get up on plane and bogs out at full throttle with a load. Idles fine. Engine compression is a little over 100 psi per cylinder, new stator, new fuel pump diaphram and gasket, carbs have been rebuilt & new plugs. Tested timing and it is advancing. Tested spark when under load with air gap checker and spark is blue on all three cylinders. Pump ball is staying fairly hard for the most part. Had the pitch of the prop checked as was told that it is ok. When the engine bogs down there is still blue spark on each cylinder. Also tried moving pin up and down to adjust engine position. The only other thing that we notcied is that the underneath of the hull has been patched from bow to stern and every time the boat is removed from the water, we pull the plug and I would say about 10 gallons of water comes out. Any ideas? Please Help !!!

When the engine bogs down does it come to an idle or does the engine shut off?
You state that the primer ball in the gas line stays fairly firm.
Have you checked the fuel system and pickup tube in the gas tank for trash, air leaks in the fuel line, or for connectors on the fuel line not connecting properly?

Taking into consideration water weight in boat hull, number of people onboard, gas in tank, patch job on bottom, how the weight in the boat is distributed.
If everyone sits in the back it may be hard to get the boat to plane, the patches on the botton if rough enough can slow the boat, the extra weight of the water in the hull, one or more of these things can possibly play a roll in the problem your having. Good Luck!

 

[MikDee]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

The recommended setting to start with on the trim rod, is when the cavitation plate, is straight (paralell) with the bottom. Also, maybe all the water you're leaking in, is rushing to the back, making it harder to plane?
Your compression is a bit low, but it still should plane off, I would check the fuel tank vent, and the antisiphon valve, & filter, in the fuel tank. Full advance on the under flywheel plate, is reached with about 1/2" of thread in between that, & the carb linkages.

 

[jerryjerry05]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Sounds like a air leak in the fuel system.Remove all quick connects and run the gas line direct.The check valve in the ball could be bad.The antisiphon valve could be defective.Get a 6 gal tank and run it on that and see if that makes a difference.In some cases the gas line could be delaminating and collapsing under full load. Luck,Jerry

 

[john from md]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Do you have a swim platform on t he boat? Some of these throw water into the grab rail which bounces it to the gap where the set back meets the boat. I took my swim platform off my Bayliner Capri and stopped having water problems.

Do you ever get to 5000 RPM? If not what RPM does it go to when it bogs out? Have you tried pumping the ball when it starts to bog? Does this do anything?

My 1985 85hp Force engine gets 150 psi when I check the compression. I do my best to keep it carbon free. 100 is too low and you need to change the head gasket and do a good decarb.


It definitely sounds like it is going lean at high rpm. The low compression may be a factor in then mix.

Regards,

John

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

OK. When the engine bogs down it will stall out and sometimes pickup if you keep it at that position but when you throttle it back it will stay running. I will run the line direct Sunday and take it out again. We tried to get it on plane with full throttle and two adults that were the only people on the boat towards the bow. I will also recheck the engine timing and sync as well. There is a swim platform on the boat. I will also check that as well. There is no RPM gauge. The only thing that I can say is it sounds about 3,000 RPMish when it starts to bog. A little more history. This powerhead was rebuilt and then sat for 1 year before we got it. Aparently the customer then took it to some guy who disassembled it and left it and then it was brought to us. We examined the cylinder walls and there was not score marks on the walls and the piston tops were clean and we resealed everything and we just put this powerhead back together and there are new headgaskets on the powerhead and they have been torqued down to specs. I will also try the decarb Sunday as well. I have the floats set so they are level with the carbs? Is this going to be OK or should I make it so the top of the float is bent towards the carb a little more so more fuel enters the fuel bowl? Thanks for all of the help. Any more ideas are appreciated. I will update as soon as we get back Sunday.

 

[gatormeat]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

I have a 1989 85 hp and the compression is 120,110,120. with two adults it jumps right up on a plane and will do 40 mph. now that was without the built in gas tank. when i connected the built in gas tank it would do as yours. what I found out in my case was the fuel tube in the tank was almost stopped up.I took it out and replaced the dip tube and fittings and will run great until my filter gets clogged. fuel sitting there for a long time will get taky (almost looks like honey).hope this helps.oh it's a 17ft capri.

 

[john from md]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

If the engine has been torn down, it should not need decarbing as then rings should not be sticking. I still say the compression is pretty low.

One thing that not many folks change that could cause your problem is the three check valves in the fuel pump. They only cost $5 apiece and two are fairly easy to change. The third needs to be pulled with a puller or a soft tube type easy out. If you are handy, you can do it. You can press them in with a socket and small arbor press or even tap them in with a hammer.

My 85hp force would intermittantly shut down and, if you pumped the ball, you could keep it going. This was the particular symptom that led me to the check valves. The old ones were plastic disks and I believe that the alcohol in the fuel today caused them to swell and stick.

Get a tach. You can't troubleshoot effectively without one. Buy one of the inductive types that sears sells. That is what I use when I tune my engines.

Regards,

John

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Thank you for the info. We tried pumping the pump ball and it was still for the most part hard and it did not make a difference. I will go to sears first thing in the morning and get this. Thanks again and I will also look into the check valves.

 

[CharlieB]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

If you get a chance, weigh the boat, ten gallons of wateris another 85 lbs, + however much has soaked into the foam core of a Bayliner.

That bottom repair may be another indication that this boat is already 'waterlogged'.

Weigh it.

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

How much should this boat weigh? We just took this thing out again and here is the scoop. Carbs Wide open perfect horizontal. Pumping primer bulb did not make difference and stayed hard anyhow. Compression reading warm is 110PSI. Drained water in hull did not make difference. Put everyone at the front of boat, 2 people, still will not get on plane. Fuel tank vent OK. Removed fuel line coupler from tank and put line direct into tank, no difference. Timing is advancing. RPMs will not go past 2010 RPM WOT. Seems to be getting enough fuel. Bright blue spark jumping gap on all cylinders at full advance and max RPM. Here is the only thing that I have left. The only thing that we have left is the prop. This guy said that the original prop got broke and they just through a prop on there. Can someone tell me what the OEM prop size is sopposed to be. The kiel of the boat has been patched from back to 3/4 of the way up the front, it was never sand down and is very rough. If someone could even call me and share advice that would be great as we are out of ideas. Our number is 716-868-0321.

 

[timdan94]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

according to the manual I have the motor came with a 13" dia X19" pitch aluminum alloy prop

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

For what kind of boat?

 

[timdan94]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

it didn't have any type of boat it was just the factory manual for the engine...

 

[buffalosmallengine]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Well I would like to thank everyone for their help. PROBLEM SOLVED !! What we did is changed the prop pitch from a 19 which from what we were told was the incorrect prop all together for this boat which is a 17 foot open bow Capri to a 15. This thing now jumps right up on plane and flies across the water at 5,000 RPMs and is fairly quick. Thanks again for all of the help !!

Buffalo Small Engine Repair

 

[maxum247]

Re: 85 HP US Marine, Force Outboard Not Getting On Plane

Gald to hear you got it figured out! max!