major major timing problem

[ebrich2]

just went through an ordeal with my 1988 mercury 150 xr4, so far this is what has had to be replaced.

stator
trigger
2 power packs
carbs taken apart and cleaned
new starter

when i get to the point of really wanting to tweak it out and start checking timing i determine that when i set #1 cylinder to tdc the .462 mark on the flywheel is about 6 to 8 inches to the left (not even visible in the timing window).

any suggestions as to why or anyone have any ideas on how to correct it?

Thanks, Ben

 

[Barnacle_Bill]

Re: major major timing problem

Not to insult your intelligence but are you sure you are using #1 cyl? Top starboard?

 

[j_martin]

Re: major major timing problem

If it runs, then what has happened is that the flywheel has been disassembled at the flex plate and put back on out of position. It will run fine that way because the magnets that drive the trigger (timing) are in the hub, which cannot be put on out of position. It's keyed. The only problem is the timing marks are off.

Using a depth gauge or dial indicator, position #1 piston (top, starboard) to 0.462" before TDC, and then take the flywheel off at the flex plate and turn it so the .462 mark is in the timing window. Then set the timing pointer right on. Don't forget the locktite and correct torque on the flywheel flex plate bolts.

If this doesn't make sense to you, then get the Mercury manual and read section 2C, "Timing, Synchronizing, and Adjusting."

hope it helps
John

 

[ebrich2]

Re: major major timing problem

thanks guys, you don't know how much i appreciate all your help. Bill i didn't take it as an insult at all and i do have a factory mercury service manual that i am using step by step. john that's what i was thinking was to take apart the flywheel but i wanted to make sure so i didn't knock anything else out of line doing it. i am really excited i am so close to getting this thing running like i want it. what's telling me its out of time to begin with is my base timing screw is out of movement, the maximum spark advance screw is out of movement, it idles at 1000 to 1100 rpm's with muffs on and my idle screw is out of movement. I'm surprised it runs at all, lol. i want to make sure it is running right before i take it to the water cause that's all i need is to ruin it trying to make it run wide open on the lake and burn or blow something up. thanks again john

 

[j_martin]

Re: major major timing problem

If you do the link n sync in order, and everything else is in order, as in no air leaks, and carbs reasonable, it'll dial right in. Might take you 2 passes first time around. Procedure can be a bit intimidating till you get your mind wrapped around it.

 

[ebrich2]

Re: major major timing problem

i hope i'm not jumping the gun but i really feel like i'm about to have a top notch running machine. the previous owner had the power head rebuilt about three years ago and from all the things i have had to change on this thing going by the manual it looks like he just through it together.

 

[j_martin]

Re: major major timing problem

When I got my XR4, it had a few obvious problems, and was generally a so-so engine. I decided to go through it and check it all out. After fixing all the misadjustments and replacing all the wrong, damaged, or inadequate parts the "certified" mechanic had done to this thing, I had to then go buy a steeper prop to keep it near 6000 rpm at WOT. I now turn a 24" five blade prop at 6100 rpm. I kept the 22 because I have a couple of morbidly obese fishing friends.

It's a labor of love. I just scattered the front third of the engine all over the rear casting deck of the bass boat, and ordered some CCM sport reeds for it. I'll detail the carbs and fuel pump when I put it back together. It's been a couple of years since the last time.

When I launch it in a few weeks, it'll be running pretty hard all summer.

Good on ya
John

 

[sschefer]

Re: major major timing problem

Hey John, Chris can cut you a set of sweet reedblocks to go with those new reeds..hehehehehe... FrankenMerc really liked them.

 

[ebrich2]

Re: major major timing problem

when i first got it, it ran good before all the little things started showing up, this is what mine could do,
wot clocked by gps at 57 at about 5800 rpm with a 25p high 5
does that sound about right?
Thanks,
Ben

 

[j_martin]

Re: major major timing problem

Prop slip is a bit high, about 22%. I'm guessing setup could be improved. What boat is it on?
On an 88 tracker, I'm turning 6000 into a 24" high five and running low 60's Gear is 1.78 I'm trading a bit of slippage for less LU in the lake (drag)

That motor's been around. The original 4", 1.78 LU has been replaced with a 4.5" 1.87. (25p High five only available in 4.5") The 4" has to be precisely maintained, well lubed, and carefully surfaced if at all or it'll put a pinion out the side. 4.5" of course has a bit more drag, but it's not a deal breaker.

 

[j_martin]

Re: major major timing problem

Hey John, Chris can cut you a set of sweet reedblocks to go with those new reeds..hehehehehe... FrankenMerc really liked them.

It's a fishin' boat. I'm mostly concerned about digestibility, but improved low speed operation would be a big bonus. I'll hand lap the stock cages and clean em up a bit before I mount the new reeds.

Motor's too old to get wild on compression and such, but when it starts to show signs of needing freshening............Like T-rex says, I'll soon be spittin' aluminum rivets.

 

[ebrich2]

Re: major major timing problem

John it is a 1988 ranger 374v bass boat. When I hit 57 it was down wind on the flint river and I had her trimmed up pretty good too. If I tried to trim it down a little she would start porposing so I'm not sure if the motor is too high or too low on the back. It also has a jack plate that is not operational at the moment. That's gonna be my next thing is to get it working.

 

[j_martin]

Re: major major timing problem

How much setback in the jack plate? Normally these type boats handle pretty well stock, and tend to porpoise a bit if you trim out at mid speeds. I have to trim it in to get the bow down at 30 or so, but fly real nice at speed. My setback is 6 inches.

It sounds like maybe you're too far back and too deep.

Set up is an art, and a lot of these old boats were way wrong. I had to raise my engine to get it to clock out like it should. Now, at speed, it'll loose water pressure if overtrimmed. When running the bow is up, but not real high, the prop is about 1/3 out, and the chines barely touch the lake. With TeleFlex NFB steering, I can let go of the helm and it's stable. (Not recommended) At lower speeds I can trim the engine for handling and run reasonably efficiently at anything over 25.

At speed I can sink a Malibu with the roost. (been there, done that)

 

[ebrich2]

Re: major major timing problem

john mine looks to be 6 inches also, and when i hit the switch nothing happens, i haven't started my diagnostics on it yet but will in the very near future. also it has a weird piece of metal rolled up and stuck in the brackets and it looks like it has been lowered to rest on that piece of metal, i know this thing sounds like it came from a junk pile lol but i am determined. it is a power lift brand jack plate

 

[j_martin]

Re: major major timing problem

Patience, grasshopper. One step at a time. You'll get it, and you'll really enjoy it.

 

[ebrich2]

Re: major major timing problem

the nightmare is over finally!!!!!!!!!!
took my boat out last evening and i have never heard it run sooooooo good, after i finally learned how to read a dial indicator!!
thanks to john and all the other members of iboats for all the help and advice! i could have never made it without you guys.
Thanks again,
Ben