Yamaha 55be (circa1991) service manual & general help with under-powered performance

[Keithbaja]

For gods sakes !! Leave the timing alone. If anything, retard 2 degrees. I can't remember the last time I had to mess with the timing. And I work 7 days a week in the boating season.. same with carbs syncing. Unless someone messed with carbs.
They DONT go out of sync very easily. I always check the cam pickup for wear and note at Idle the gap or da mark
I also always ck carb throttle plates for WOT. You be surprised from the factory they are close, but not Wide open. I have also seen them open past the correct mid way point.. always remember, boat builders are fiberglass/alumanan pros not propulsion experts. Same goes with alot of boat dealers..

[Neils6896]

I noticed last night quite a lot of fuel in the base of the top unit. No signs of leaks from any of the fuel pipes or pump. Could this be from over fuelling? Could that also be causing the 2nd cylinder not to run?

[99yam40]

I noticed last night quite a lot of fuel in the base of the top unit. No signs of leaks from any of the fuel pipes or pump. Could this be from over fuelling? Could that also be causing the 2nd cylinder not to run?

not sure what you are referring to"in the base of the top unit"

Have you checked to fuel pump yet like I said twice already?

[Neils6896]

not sure what you are referring to"in the base of the top unit"

Have you checked to fuel pump yet like I said twice already?

See attached.

Sorry yes thought I'd already said, checked all fuel line and fuel pump and can't see any leaks and doesn't appear to be blocked either as fuel is getting to both carbs.

[99yam40]

how did you check to see if fuel is leaking into the crankcase from the fuel pump?
I am guessing this motor has the fuel pump tied to the bottom cylinder crankcase to use the pulse to operate the pump like most all others.

did you sync the carbs after you put them back on?


fuel should not be where you are pointing to,
find where it is coming from before it catches on fire

[TownsendsFJR1300]

Obviously NO fuel should be in the lower cowl.

Dry it real good with a rag and/or air compressor.

Might try squeezing the primer bulb till hard, your leak will possibly show itself with that pressure. ..

Carbs, per your PDF are at the other end of engine(front) so fuel must be running downhill to that area.

Looking at a parts diagram for an engine CLOSE to yours doesn't show the fuel pump.


Can you post a pic of where the fuel pump is, if attached to a carb(often the lowest carb) or is separate?

.

.

[Neils6896]

Obviously NO fuel should be in the lower cowl.

Dry it real good with a rag and/or air compressor.

Might try squeezing the primer bulb till hard, your leak will possibly show itself with that pressure. ..

Carbs, per your PDF are at the other end of engine(front) so fuel must be running downhill to that area.

Looking at a parts diagram for an engine CLOSE to yours doesn't show the fuel pump.


Can you post a pic of where the fuel pump is, if attached to a carb(often the lowest carb) or is separate?

.

.

Thanks Townsends, fuel cleaned up, gave the primer a good squeeze and no obvious leakage, primer ball nice and firm so I'm thinking now maybe it was a spillage from when i took of the carbs and checked the fuel lines previously. Will keep a close eye on it. (pdf attached of pump location - separate from carbs)

[Neils6896]

how did you check to see if fuel is leaking into the crankcase from the fuel pump?
I am guessing this motor has the fuel pump tied to the bottom cylinder crankcase to use the pulse to operate the pump like most all others.

did you sync the carbs after you put them back on?


fuel should not be where you are pointing to,
find where it is coming from before it catches on fire

Hi 99Yam, As above i squeezed the primer ball and looked for any obvious leaks around all fuel lines for any obvious leakages. all lines and joins seemed bone dry.

No didn't sync the carbs, wouldn't know how or even that i was mean to!?

Pump location attached...

[Neils6896]

Also i know you lot are going to give me a load of abuse for this but in my frustration with getting it running properly i thought i would change the prop and impeller, I consulted a load of youtube vids on both and thought it was really simple.... I now seem to have it stuck in forward gear! Tried to take her out yesterday but she stalled or wouldn't each time in the water but fired right up out of the water.

I removed the lower unit again and tried realigning the gear road and the pin on the lower unit (both in the same position each time either fwd/neutral/revrs with the throttle control in the corresponding position) however this didn't seem to make any difference when trying to put it back in neutral. I took the lower unit off again and noticed that which ever position the gear pin is in it wont put the prop shaft in neutral (won't spin freely) Seems like it's locked in gear within the lower unit (gear casing?!?) help!!

[99yam40]

if this is a twist to shift and not a push/pull, then turn the shift shaft until you hit neutral.

like I said in that other post you just posted on protect the splines and grab with a pair of pliers and turn.
you will have to overcome the spring to get to neutral and reverse

also you will have to remove the fuel pump from the block to see if fuel leaks from the pulse port.
that is the only way for the fuel to get into the crankcase.
leaking on the outside will not get into the crankcase

your service manual should give you procedures for link and syncing the cabs after installing them.
if you cannot do it find someone that can and watch them so you know for next time.
that includes making sure timing is correct

[Keithbaja]

99yam40, sir timing and carb syncing is almost never, ever needed ! I have around 40years in this biz. Outboards do not fall out timing. Unless something gets really, really worn. Same with carb sync.. I understand your trying to help, but giving bad advice dosnt help his issue. I get calls everyday from outboard owners asking for a tune up....there is no such thing !!! Look in a factory service manual and show us. Post a tune up from any outboard maker and I will eat my hat. Gee, spark plugs last how many miles/hrs in a car/truck motor ? They do not go to hell in boat motor faster.. GRrr !!

[TownsendsFJR1300]

99yam40, sir timing and carb syncing is almost never, ever needed ! I have around 40years in this biz. Outboards do not fall out timing. Unless something gets really, really worn. Same with carb sync.. I understand your trying to help, but giving bad advice dosnt help his issue. I get calls everyday from outboard owners asking for a tune up....there is no such thing !!! Look in a factory service manual and show us. Post a tune up from any outboard maker and I will eat my hat. Gee, spark plugs last how many miles/hrs in a car/truck motor ? They do not go to hell in boat motor faster.. GRrr !!

Had an original spark plug go bad in my '06 F150 with less than 150 hours TOTAL (and was never previously touched).

Caused max RPMs to drop (on and off) from 5,900 to under 5,000 (as ignition cut in and out with the bad plug ((as I later found out))


Spoke with the shop, told them of the issue, said it was way overdue for plugs. Huh???

Swapped all 4 plugs (all looked the same), THAT (one plug) was my issue

.

[99yam40]

99yam40, sir timing and carb syncing is almost never, ever needed ! I have around 40years in this biz. Outboards do not fall out timing. Unless something gets really, really worn. Same with carb sync.. I understand your trying to help, but giving bad advice dosnt help his issue. I get calls everyday from outboard owners asking for a tune up....there is no such thing !!! Look in a factory service manual and show us. Post a tune up from any outboard maker and I will eat my hat. Gee, spark plugs last how many miles/hrs in a car/truck motor ? They do not go to hell in boat motor faster.. GRrr !!

You are very wrong on several accounts.
But you did leave yourself an out by saying almost never

when a motor has an unknown problem, you check the easy things to do 1st to make sure they are in spec.

when someone brings in a motor with a problem, you have no idea who has played with it in the past or what they have done to it

Mutli carb motors should be link and synced every time the carbs are put back on the motor to make sure they are all set to close exactly the same.
the bolts that hold them on are not precision fitted so the carbs may not be exactly the same as they were last time installed.
timing is part of the link and sync.
The OP pulled and put the carbs back on with out knowing he should do the link and sync.
I told him to follow the procedure in the manual, that is why they put the procedures in manuals

I have found more than one motor including my C40 that the idle timing was way off and the only way to correct it was to replace the CDI.
apparently the build in TPS (wiper) had a problem, others were just someone playing with linkages.

Not all older motors had a timing plate with mechanical linkage to control the timing.
you must work on very old motors if that is what you see all of the time.

I also found someone had drilled out the mail jets on my preowned C40 somewhere down the road before I got a hold of it
hard to find since the jets had the proper numbers and I could not find a chart the listed what size the orfices should be.
you need to eliminate all you can by verifying everything is in spec that you can 1st and then chase what you cannot

spark plugs do go bad internally some times, and some times they just carbon up and need cleaning or replacing.
I have even found some that were eaten away and way out of spec, but that was long ago

[Keithbaja]

Hi 99yam40. You confuse me about working on older motors. No worries mate. Yes plugs do go bad. And in many ways. Example on Ficht's the plugs get so caboned up in as little in 5 hrs. Do you know that if you ever drop a plug,, you throw it away and get a new one. The cathode and annoid are pretty tuff. The ceramic is not. I've noticed many, many boat owners are constantly replacing their plugs. Cranking, compression. Lack of fuel or too much. And avable Kv to the plug.. is sorta the diagnostic start. I'm not in a pissing contest with you. You seem like a great guy on this blog. And have made some great, helpful, nice post's and reply's. And mostly on the money. Thank you. Seldom is timing a issue. This is fact. Yes new and old motors can lose their timing from many caus
es. Ever see sheared flywheel keyway ? I have seen one in my long career. And I think along the line that anything can, will go bad. When motors that gets used on somewhat reg bases. Its almost always one or two issues. SO let's carry on and G'day sir

[99yam40]

found a few lawn mowers that sheared keys, but not an outboard yet.
but have heard of that happening

I have found brand new plugs bad before when working as a auto tech back in the early 70s, so yes dropping anything ceramic is bad for it.
if you do not link and sync carbs after putting them back on, I am not sure about you having that many years in this

As I said compression, spark and timing are too easy to test to not do it.
no reason to look anywhere else if any of them are a problem.
if one is a problem then find out why and fix that before going farther.

been playing with mechanical stuff for as long as I can remember.
use to have parents bring their kids motor bikes to me to work on when I was in the 5th grade.
loved the stuff.
had to know how and why things work.
guess I should have gone to collage to become a engineer, but working with my hands was the way I liked it.

thanks for the kind words, but you need to lay off telling the people looking for info to find a tech to pay.
if you know something, help others when you can

Oh yea, older motors can mean different things to different people
how far back have mechanical timing plates been used, or better switched to electronic con*****ed?
20 or 25 years
centrifugal and vacuum advance has been around for a very long time on a lot of motors out side of outboards