125 hp force not getting up to speed.

[derekshep]

ok guys and girls, i have been reading around on this forum for couple weeks and now have my first boat. it has a 1989 125hp force. got the motor running and while in neutral it will rev, but when in gear its nt rev'ing up to full power. top speed wa 18 mph. i hae a 1988 sea ray seville. now for what i have checked.

-compression on all cyl. are good 145-150.
-spark to all cyl.
-fuel tank has been emptyed and cleaned
-carbs opening fully
-idle screws are 1 1/2 turns out.
-floats are not stuck

dont know what next to do.

 

[Frank Acampora]

Re: 125 hp force not getting up to speed.

Do you have a tachometer? is the engine revving to 4500-5500 at full throttle? Will the boat plane?
If so, FIRST: Suspect the speedometer. They are notoriously inaccurate. Look at the transom and see if the impact fin is flipped up. It will be a small black or white plastic fin at the bottom of the transom. Next check for a kinked pressure tube.

If you are getting a low speed on an accurate meter liike a GPS, then start troubleshooting.

 

[steveclv]

Re: 125 hp force not getting up to speed.

You should be able to tell the difference between 18mph and the 40mph that the boat should reach if you have ever ridden a motorbike or put you hand out of the window of a moving car but you do need a GPS speed and revs before you start trying to fix things. There are free GPS apps for iPhone and Android smartphones that are very accurate.

Assuming that you are correct and the boat is only pulling 18mph and probably about 3500 rpm - how does it sound at full throttle? Is it missing, slowing down, jerking? Describe exactly what you are doing and how it feels and sounds.

 

[derekshep]

Re: 125 hp force not getting up to speed.

it is only going by my htc hero app. sounded about 1/3-1/2 power. rpm was running about 3200.

 

[steveclv]

Re: 125 hp force not getting up to speed.

Was it jerky or smooth?
Has it ever run faster while you have owned it?
Do you know the size of the prop?
Check the timing.
It could be damaged reeds - Frank may have more info on those and if they could cause low power
It's possible that your crankcase seal is leaking but that's a long shot.

 

[derekshep]

Re: 125 hp force not getting up to speed.

bought the boat month ago with rotten inside. have stripped and almost done with the inside, had theboat on water twice, first time it ran 13mph, found the ground from the coil broken off, conected it and took her outagain to see if that changed anything. that time is when i got 18 mph. the motor while in gear soundsfine, other than not reving up fully. doesnt jerk. but in neutral when reved it is a little jerky, kindof like it is not in time or not running on all cyl's. so i was going to pull each plug wire to check if the motor changed and when i pulled the first one i got shocked, but the motor changed. so the first cyl is firing, didnt feel like getting shocked again so havent checked the other 3 yet. should i get shocked like that. all i was touching was the wire nothing else. dont know the prop size haven't looked. my keyway in the flywheel broke in half, so i had to pull the flywheel and put a new one in.

 

[steveclv]

Re: 125 hp force not getting up to speed.

Yes you will get shocked - 40,000 Volts has to go somewhere when you take the wire of the sparkplug

Use insulated pliars to pull the wire off - it's a good way of testing whether the problem is one cylinder or all cylinders.

You need to check the timing too - use an inductive timing lamp connected to the top cylinder - pull the plugs out and wrap wire around them to ground them and then put the throttle on full advance. Apply 12V to the yellow wire of the starter solenoid and check that the timing mark is aligned with the pointer above the carbs. I'm worried about this because if the PO didn't know about the broken key in the flywheel, he may have attempted to re-time the engine after the flywheel slipped. Now you have returned it to factory with the new key, the timing may be way off

 

[derekshep]

Re: 125 hp force not getting up to speed.

i just put the new keyway in, didnt change anything

 

[derekshep]

Re: 125 hp force not getting up to speed.

the keyway broke after i got the boat so the timing hasn't been changed.

 

[steveclv]

Re: 125 hp force not getting up to speed.

Well if compression is fine, carbs are close enough and the throttle plate opens fully and you are certain that the timing is correct then you need to check that it's firing on all cylinders so go back with rubber gloves and insulated tools and pull a plug wire at a time at about 2000 rpm or less.

If you have one cylinder that seems to be less effective than the others, swap the spark plug with another cylinder and then try swapping a coil pack.

If it's firing ok on all cylinders and each plug wire removal has the same effect then it's back to one of my original thoughts that it may be damaged reeds.

 

[derekshep]

Re: 125 hp force not getting up to speed.

i dont know that the timing is correct, i just didnt change anything after the flywheel slipped. i think i am going to go threw the whole motor, pull carbs clean then, clean all fuel hoses and check everything from top to bottom. sorry for the newb question but what are the reeds?

 

[steveclv]

Re: 125 hp force not getting up to speed.

The reeds are thin metal or composite blades or petals that cover the inlet ports and work to help the air/fuel charge get 'pumped' into the cylinder - they are meant to sit in a closed or almost closed (I believe the spec is like 0.010" open) and they open and close under air pressure pulses. If they get damaged then they can affect the power output of the motor.

 

[SwampThing]

Re: 125 hp force not getting up to speed.

I'll bet you have a coil that's failing. I just replaced the second coil on my 86 125hp in the last 2 years. What happens a lot is the plug wire is actually what's bad. These engines are getting old and plug wires don't last forever. Unfortunately you can't replace just the plug wire on the original coils. The new replacement coils have replaceable plug wires. Lucky for me I just picked up a entire working working parts motor for $200.

A defective plug wire will fail more at higher speeds. On my boat the symptoms were such that it was hard starting, would run fine up to about 1/2 or 3/4 throttle and then start bogging intermittently between 3/4 and full throttle. I fish a lot at night and when you need that full throttle to fight the 3 foot chop for the 5 plus mile ride back to the dock in the dark, well it tends to scare your passengers a bit.

Pulling the plugs and checking for spark can be somewhat problematic if the problem is intermittent. The first time I checked for spark, I had spark on all four plugs. A few minutes later when I checked for spark only 3 plugs were firing. From this point on the fourth plug never did fire again, but my inductive timing light would fire depending where along the plug wire the lead was placed. I knew what was up since I went through this once before.

NEVER just pull the plug wire to check for spark. You're begging to blow a CDI unit. Pull the plugs and ground them using pieces of wire electrical taped to the outside threads of the plugs and run to a good engine ground. Swing the plugs off to the left side of the engine where the coils are (you'll be able to watch them while turning the key yourself) and I use a piece of cardboard to shield them from any fuel mixture spraying from the open plug orifices and thus starting a fire.

If one plug doesn't fire or has a weak spark, first try switching the plug with one of the others. You could have a defective plug. Next try switching the feed wire for the coil in question. See if the problem changes. If no change, switch the feed wire to the coil with a feed wire from a different CDI pack.

If you switch the feed wires around and the same plug will not fire or fires intermittently then you have a defective coil.

 

[derekshep]

Re: 125 hp force not getting up to speed.

ok, new update, today i found out that when shes running, cyl. 3 & 4 when unpluged do not change the motor at all, so that means cdi pack right?

 

[SwampThing]

Re: 125 hp force not getting up to speed.

Did you check to see if you have spark on those cylinders? To check for spark you need to pull the plugs and ground the outside thread of the plugs with a piece of wire. The if indeed you have no spark on #3 & #4, you'll need to start diagnosing your way back through the ignition system.

Being that you said the key way was broken on the flywheel, I'd would take a good look at the pick up, stator, and for damaged wiring in that area.

Also when you get this issue resolved, replace the fuel pump diaphragm. You never mentioned doing that in your original post.

 

[derekshep]

Re: 125 hp force not getting up to speed.

forgot to post that i have replaced all fuel lines, bulb, diaphragm, pulled and clean whole tank, vent tube, and pickup line. i put a spark tester on all cyl and they are all firing. checked all wiring and found a ground wire from bottom of coils not hooked up. so i hooked it back up to the block. what would the next step be? do the carbs feed the whole motor or they linked to cyl. (like top carb feeds top two cyl. and bottom carb feed bottom two cyl.)

 

[steveclv]

Re: 125 hp force not getting up to speed.

Top carb feeds 1&2 - bottom carb feeds 3&4

So if it's not spark it's either carb or reeds.

 

[derekshep]

Re: 125 hp force not getting up to speed.

so how do you know if its bad reeds? wht what is the best reeds to buy for this motor

 

[derekshep]

Re: 125 hp force not getting up to speed.

ok well went shopping today, surely something i bought will fix the problem.

stator
2 x switch boxes
4 x coils
timer base / trigger assembly
starter solenoid
wire junction
4 x reeds

pretty much everything but the carbs. pulled carbs off today and cleaned them checked foats again and put them back on.

 

[steveclv]

Re: 125 hp force not getting up to speed.

Remember to replace one item at a time

Worst case you can sell the other new items on eBay - best case you can return them for a refund

If you change everything at the same time then you will never know what was causing the problem.

PS I like your style