Force 125 Discrepancy re timing in FSM

[docimastic]

I have a Force factory shop manual for my 1988 125, which I set at 28 degrees static, per what I've read on this forum and elsewhere. FYI, my flywheel does have all 3 timing marks... 28, 30, and 32 degrees (as well as the TDC mark) ....

At the very front of the FSM (Section 1 "Specifications") it clearly says "Timing Wide Open Throttle 32 degrees BTDC. The SAME manual, at Section 3A (CD Ignition (Prestolite)) ..and yes, I have the Prestolite ignition.... states " In order to obtain a 30 degree timing while the engine is actually running, it will be necessary to time the engine to 28 degrees at cranking speed." That is what I did...even though I have NO idea why the timing changes from cranking to running.... Also, in Section 3A, the manual states "The engine timing specification for all FORCE engines with adjustable timing is now set at 30 degrees Before Top Dead Center (BTDC) at Wide Open Throttle (WOT). All current production three and four cylinder engines have timing marks ...." [showing the 28, 30, and 32 degree marks]. Note that it does not state whether that 30 degrees BTDC at WOT is running or static, although in the same section it does talk about testing with a test wheel (we all have one of those, right? hahaha) and checking that timing is 30 degrees at WOT.

And yes, I know that Frank Acampora (who, IMHO, shares the throne with Jerryjerry as King of Force knowledge! My THANKS to both of them for ALL of the GREAT info they've posted!) in his tutorial video states "These particular engines need to be times at 30 degrees running, which translates to 28 degrees at cranking speeds."

Sooooo... Did Force change the timing from 32 to 30 degrees (running) at WOT?

FYI ... I run 89 octane ethanol free fuel.

Anyone have any thoughts on the apparent discrepancy in the shop manual? And... I'd love to get a few more RPM if I can SAFELY do that by advancing the timing to 32 degrees (running) at WOT.

Thanks in advance for your thoughts.

David

 

[Nordin]

I know this is a bit confusing and I do not know why the manual states different timing advance.

My opinion is to set the timing at WOT to 28 dgr or 30 dgr.
It does not matter with those 2 dgr, but with the "bad" fuel nowadays it is better to retard the advance to 28 dgr.

To much time advance will increase risk of pre ignition and the engine will last much longer and will "feel" better with 28 dgr spark advance.
This is my personal opinion and I am a person that do not want kill old engines. Better to run them with calm and not squeeze the **** out of them.

 

[docimastic]

Thanks for your thoughts, Nordin. I, too, do not want to kill old engines, which is all I have ...(also have an 87 Suzuki DT55, which, FYI, sets the timing electronically), Yes, probably better to err on the side of caution, as you suggest.

My 125 Force is on a Bayliner Trophy 1910 (18' 7" centerline length with center console). With the timing set at 28 degrees at cranking speed, I am getting 4950 - 5000 rpm (running a 13X17 SS prop) and 38 to 39 mph (via GPS) in choppy water, which I have read is what to expect from this setup. Some day I will a chance to take it out at night (so I can see the timing light!) with another person to man the helm, and check to see if I am at 30 degrees at WOT under load.

I should add, re the discrepancy in the manual, that it is not the first time I have seen errors in FSMs.

David

 

[SkiDad]

well I'll chime in on my experience. 1st off, you probably know this, but the marks from left to right are 32, 30, 28. Set it to the middle one at cranking and that will put you to 32 degrees. I ran my 1985 force 125 at 32 (30 crank).

I think the misunderstanding about all of this comes from the fact that some folks get gas from marinas which can loose octane from sitting. That is why force suggested running at 30. If you get gas at a local gas station (on the way to the lake) there is no issue running 32 degrees.

that said, i don't think you will see a ton of rpm change - maybe 50 or so.

I don't think i would test the timing when driving, that could be a bad decision.

on my old setup i had a 19' bayliner - it weighed about 1500 lbs with engine. I ran a 15 pitch stainless prop and that put me about 5400 rpm - it ran about 37-38

 

[legalfee]

I thought that you set the timing to 30 degrees static at WOT and that equated to 32 degrees with the motor running. Am I wrong?

 

[docimastic]

Legalfee, try as I might, I wasn't very clear. Sorry about that. I set the timing at 28 degrees at cranking speed ("static") so presumably is 30 degrees at WOT under load.

Skidad, thanks for that info about running your 125 at 32 degrees without issue. Yes, I am familiar with the 3 timing marks (plus TDC, of course). I suspect you may well be correct about octane degradation at a marina. I also kind of suspect (and you almost infer that you suspect this, too) that Force changed the timing specs down 2 degrees. I may just try advancing to 32 total under load... If only a 50 rpm gain, will probably set it back to 28 /30. But if 200 or more rpm increase, I will likely leave it at the higher advance. With my boat, the difference between 4200 and 5000 rpm is 8 or 9 mph! Part of that is that prop slip decreases as speed increases, so one actually runs more efficiently, methinks.

Your comment about "I don't think i would test the timing when driving, that could be a bad decision." made me chuckle.... I DID say "with someone else at the helm." Definitely would be inviting disaster to try to do it alone .....

Ever so slightly off topic, but definitely related and again, a seeming discrepancy, is that my FSM shows the 85 rated at 85 BIA HP at 5000 rpm, but shows the 125 at 115 BIA hp at 4750 rpm. BUT the Force 125 owners manual I have (year unknown, as I downloaded it from Scribd ...let me know if you want a copy, anyone) shows it at 125 hp at 5000 rpm. Hmmmmm.

Thanks, David

 

[Jiggz]

The Clymer manual refers to two types of timing depending on the ignition system, i.e. Prestolite or Thunderbolt (also year and HP and model). As previously mentioned, with Prestolite static or cranking timing is set to 28 for a 30 degree dynamic equivalent. And for Thunderbolt systems, static or cranking is set to 32 for a 30 degree dynamic equivalent. Dynamic is the actual WOT on water or with a test wheel.

And then on other manuals, it clearly states to set the Prestolite static to 30 for a 32 dynamic equivalent. I guess this is the old original setting and was eventually retarded 2 degrees with the intro of ethanol in gas. If you have yours set to 32 dynamic and not experiencing any form of back firing, I guess you are doing fine. Personally, I have it set to 30 dynamic (28 static). Back fires can be very damaging as you will read through some of the posts.

 

[docimastic]

Jiggz, thanks for your thoughts. VERY interesting about "The Clymer manual refers to two types of timing depending on the ignition system, i.e. Prestolite or Thunderbolt". (On a side note, doncha just love some of the names OB motor manufacturers come up for their "new and improved" ignition systems? ...Mercury comes to mind as the "champion" of this.) Also very interesting that that the Thunderbolt dynamic is 2 degrees retarded from cranking speed timing, the opposite of the Presolite system. Make me scratch my head! LOL

Also very interesting (to me, at least haha) about "And then on other manuals, it clearly states to set the Prestolite static to 30 for a 32 dynamic equivalent." And then you go on to say " I guess this is the old original setting and was eventually retarded 2 degrees with the intro of ethanol in gas." I suspect you are correct re "the old original setting", as this seems consistent with what I copied from my manual in my original post, which is "the manual states "The engine timing specification for all FORCE engines with adjustable timing is now set at 30 degrees Before Top Dead Center (BTDC) at Wide Open Throttle (WOT)." "NOW" set to... implies that it was different, previously.

I am set at 28 degrees at cranking speed. May try advancing it 2 degrees (as I previously wrote) but will be on a careful watch for backfiring. Obviously, not a good thing. The biggest risk re backfiring, that I can think of, is blowing out the top and bottom crankshaft seals. (NOT GOOD!... UGH) Is there other damage that can be caused by a low or cranking speed backfire? okay... yeah, I will search the posts...

Thanks,
David

 

[SkiDad]

Ever so slightly off topic, but definitely related and again, a seeming discrepancy, is that my FSM shows the 85 rated at 85 BIA HP at 5000 rpm, but shows the 125 at 115 BIA hp at 4750 rpm. BUT the Force 125 owners manual I have (year unknown, as I downloaded it from Scribd ...let me know if you want a copy, anyone) shows it at 125 hp at 5000 rpm. Hmmmmm.

Thanks, David

i had both the force shop manual (1985) and the clymers manual (1996) - I've since given both away but I remember seeing the 115 hp at 4750 in the shop manual. That's probably more accurate. Either way 10 hp doesn't mean alot.

yes the shop manual showed 32 degrees and the Clymers showed 30 degrees. In fact when I got my boat it was set at 34 degrees b/c the PO didn't understand timing or other carb settings. It ran at 34 for 25 years before I got it.

when I ran at 17p prop i could touch 40 mph so you are in the right area. Force's never had a lot of top end so you are fight a loosing battle. But I must say both Force engines we had ran really well.

if you do change the timing you will need to re-adjust your idle.

 

[docimastic]

SkiDad.. Made me smile that you remembered "seeing the 115 hp at 4750 in the shop manual". BUT...can you remember important stuff?? LOL About the 10 hp not making a big diff, I agree, but that could explain a lot of comments about the 125 being "weak".

VERY interesting post re the timing specs in the different manuals, thanks, and that yours had been set at 34 degrees! I am glad you still like to help with Force outboards....

What model Bayliner did you have that weighed about 1500 lbs with the motor? My 1910 Trophy shows (per Bayliner document) as weighing about 1900 lbs with the 125. Maybe that includes the trailer? I have not yet, but am going to, get a certified scale reading for the trailer with boat and motor, and the trailer itself.

Funny how time changes specs and perspectives... I have read many posts commenting that Bayliners were kind of slow / underpowered. I am almost 70 now; when I was growing up anything over about 35 mph on the water was pretty darn fast. My family did have a 21' Century (double planked mahogany.. no fiberglass when she was built!) with a 300 hp Buick (yes, you read that right) engine that would do 54 mph. Probably was the fastest boat in Sarasota other than the "Umbriago", a Jr. Prowler V drive with a Cadillac engine, built for racing. Nowadays every boat one buys, it seems, will do 50+ mph.... Ah, but I digress....

Thanks, again,
David

 

[jerryjerry05]

The 2 degrees won't get you much in speed if any at all??
You don't need to run anything but regular fuel.
Premium isn't good for an outboard, something about flash points and longer burn doing damage.
Google reg. vs premium.

Running at speed and trying to time the motor?? Not for me. Way to dangerous.
Static timing has always done the job.
But do start it in the dark and look for spark leak.

The blowing out the top/bottom seals? I'd worry more about blowing the port cover gaskets.
One tiny pop and you've got an air leak and trouble.

 

[SkiDad]

Trophy is a heavier and better boat. i had a 1985 Bayliner Capri 1900 at 1555 lbs - it probably was 1800 with gas and all my skis. We setup our boat for slalom skiing so that is why i ran such a low pitch prop. In fact the 15p alum would hit 6000 rpm with just me. At one point i changed the lower gear ration for 2:1 - i could get up on slalom with 6 people in the boat - but like I said it topped out about 36 with that setup.

my new boat has 375 hp and uses 1/2 the gas - definitely a different beast

Sounds like your motor is pretty strong ! - i probably wouldn't change much - i learned the hard way too much tinkering caused me grief. I'll PM a link

 

[docimastic]

Jerryjerry... Thanks for your input. ALL good points! Especially re regular gas and the port cover gaskets. Good idea about checking in the dark for spark leaks, thanks Re regular gas.. gonna google it... I have never understood why people use premium in a car that call for regular. I mean, Yes, I DO love to learn stuff!

Skidad... I used to be pretty decent slalom skier.... Even had a Joe Cash slalom ski that he gave me when i was in or just out of high school. Could touch my elbow in the water on a hard cut. Now... I don't have the strength to get up on one ski. DAMN old age! Grrrrr

Yah, Bayliner shows the 1985 Bayliner 1900 bowrider at 1555 lbs with motor, as you said. Interesting that my Trophy 1910 (within an inch of the same length as your 1900, but weighs almost 350 lbs more. I can't help but wonder where the extra weight is due to.

And yes, i get it about tinkering with things that don't warrant tinkering. "If it ain't broke, don't fix it!" Seems like I am getting all of the performance from my rig that I can reasonably expect, so likely will keep it as it is.

Thanks to both of you for your input,
David

 

[jerryjerry05]

The extra weight is probably that your Trophy has a fiberglass liner and it weighs a lot more.

 

[docimastic]

Thanks, Jerryjerry.... But.... When you say a fiberglass liner, what do you mean?
Thanks... Hope you're having a great weekend!
David

 

[jerryjerry05]

The trophy is an all glass boat.
The deck you walk on is glass.
That's called a liner.

 

[docimastic]

Jeryyjerry..... as a footnote to, and validation of, your comment about only needing to run regular gas, that is consistent with the Force 125 owner's manual I have which says:
GASOLINE SELECTION
Use 87 Octane Minimum (as listed on the pump)
1st Preference - Leaded regular or unleaded regular (from a major fuel supplier)
2nd Preference - Leaded regular or unleaded regular
3rd Preference - Regular with maximum 10% ethanol or maximum 5% methanol

(Kind of interesting to me that even back when they give the OK to E10....)

And yes, despite many posts about people running 92 or 93 octane in 2 strokes for years, without issue (as well as similar comments re 87 E0 and 87 E10) as far as your comment that "Premium isn't good for an outboard, something about flash points and longer burn doing damage" higher octane DOES have a slower burn... which, according to some, allows the incoming charge to mix with the still-burning ...because of slower burn due to higher octane .....exhaust as the piston has both intake and exhaust ports uncovered at the same time, which causes premature ignition of the incoming charge, possibly even igniting the charge still in the crankcase. Without knowing, I suspect that the negative effects of the slower burn will vary with both piston top design (flat vs. a "deflector", rpm, and load.

Thanks again for your valuable input and sharing your experienced-based knowledge. You have helped many, many people on this and other forums!

David

 

[docimastic]

Just now saw your explanation, Jerry, re the glass liner. Thanks much for that. Makes perfect sense. AND helps explain why I have no soft spots in the deck that is walked on.....thank goodness. I know that some other model Bayliners (the smaller Capris come to mind) have a wood deck.
David