94 150 XR6 merc won't start?

CaptainBruce · Jan 10, 2008

Hi All...
New to the forum,
and looking for a little help?
A little history...About 2 years ago The oil injection pump quit working causing my motor to lock up. I really wasn't sure what I wanted to do with my "Classic" Ranger Bass boat.(Junk it or fix it?)
I covered it and let it set for about two years..
I finally decided I really miss playing with that boat and now want to fix it...
I wanted keep the cost down ...so ,so far I have done all of the work myself.
I bought another used block ,that was is working condition.I checked the compression and that seems fine.I also replaced all of the vacuum lines,water lines,fuel lines,and hoses.I disconnected the oil injection system (this time) because I will add the oil to my gas.I don't want this motor to lock up like the last one did.
Now my problem....I have spark and gas (I took all of the plugs out and shot a little gas/oil mix into the cylinders...and all the motor will do is back fire about every 15 seconds...
Any Ideas on why it won't start?
CaptainBruce

Windykid · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Welcome to I Boats.

What are the comression readings?

Are you getting fuel past the carbs? Have you sprayed some mixed fuel into the carbs?

Windykid · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Oh yea, Is the lanyard hooked up?

hkeiner · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

A backfire seems to indicate a possible timing issue.

You don't indicate if you have done all of the link and sync procedures after putting your motor back together. The link and sync steps would be in your shop manual. The 1st step, where you set the timing pointer, is very important when you have removed the flywheel for any reason. While all the other steps are also important, they are all depenant on the the 1st step being done correctly.

Below is an EXAMPLE from my shop manual for my motor. Your motor's specs may be different. Be sure to follow your shop manual's instructions.

---------------------------------------
TIMING POINTER ADJUSTMENT (example)
-------------- ------------------------
1. Remove all spark plugs and install Dial Indicator
(91-58222A1) into No. 1 cylinder (top cylinder,
starboard bank).

2. Turn flywheel in a clockwise direction until No. 1
piston is at top dead center (TDC). Set dial
indicator at “O” (zero) and tighten indicator set
screw.

3. Turn flywheel counterclockwise until dial
indicator needle is approximately 1/4-turn
beyond .462 in., then turn flywheel clockwise so
that dial indicator reads .462 in. (11.7mm)
exactly.

4. Reposition timing pointer (a) so that timing
pointer is aligned with .462 in. mark on timing
decal. Retighten pointer attaching screws (b)

5. Remove dial indicator from cylinder.

CaptainBruce · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Hi All,

and let me answer the threads...
The kill switch works(I have spark)
The compression is around 80,
I haven't checked the timing,I figured it would at least kick over even if its out of time?
Thanks again for the quick responses,
CaptainBruce

DJ · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

80 psi is REAL low.

Windykid · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Did you buy it with 80 psi or is that after installation?

CaptainBruce · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

80 is cold numbers...the Head was setting in my garage for about 6 months.
It sounds like I've been taken...The guy I bought it from already had it off of his motor?(I guess that should of been a red flag?)
I Think I just got screwed!
I didn't check the compression till after I installed it....
Lesson learned!
CaptainBruce

Windykid · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

It is still rebuildable.

CaptainBruce · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Any Idea what it usally takes to rebuild? (in parts and money?)
has anyone out there rebuilt a merc 150?
what was the approx cost for parts?
CaptainBruce

Windykid · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

AAAHHHHHH your on I-Boats. Just go up top and click on the links to the store motor and parts.

CaptainBruce · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

Thanks,Wendykid and all,
You guys have been a lot of help...
I think... I will at least put a set of new rings in it and see what happens?
any lessons learned form anyone?
captainBruce

DJ · Jan 10, 2008

Re: 94 150 XR6 merc won't start?

CaptainBruce said:
Hi All,

and let me answer the threads...
The kill switch works(I have spark)
The compression is around 80,
I haven't checked the timing,I figured it would at least kick over even if its out of time?
Thanks again for the quick responses,
CaptainBruce

Are you sure you have all the plugs wires on the right plugs?

Don't ask me how I know this.

The "backfire" is a sign.

Windykid · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

DJ said:
Are you sure you have all the plugs wires on the right plugs?

Don't ask me how I know this.

The "backfire" is a sign.

If this is the case and it starts, run some seafoam through it and see if the compression comes up.

rodbolt · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

if it backfires occasionally something is way off. could be you mixed up the wiring on the switchboxes or the ign coils. it happens.
you will note from the pulser coil and stator to the switchboxes one set has a yellow sleeve,all pulser and charge coil leads with a yellow sleeve must go to the same switch box, same as the harness from the switchbox to the coils, they have to go to the correct bank and the correct cylinder.
if not it will still spark just fine just not at the correct time.
while 80 PSI is low it may be your guage.
if in doubt have a leakdown test run.
80 on all six would tell me its not damaged
80 on one and 140 or so on the rest would scare me.
thats why they dont give specific numbers in most manuals. we can keep the guges metcaled.
would drive the price of a guage set through the roof.
usually you get 10 PSI from hihest to lowest reading as being acceptable or 15% leak down.

MikDee · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

DJ said:
Are you sure you have all the plugs wires on the right plugs?

Don't ask me how I know this.

The "backfire" is a sign.

LOL, I agree, Been there, done that.

CaptainBruce · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

RedBolt,
Thanks for the Info....
I bought a new gauge (My old one was one that had a rubber tip on it) but this one screws in.Her are my readings
Cyl
1 95
2 95
3 115
4 110
5 95
6 115
but how do you do a Leak down test?

Windykid · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

"http://www.aa1car.com/library/leakdown.htm"

Here is a link for a leakdown test.

rodbolt · Jan 11, 2008

Re: 94 150 XR6 merc won't start?

the port and stbd banks are runnig fairly equal. not uncommon to see a spread between banks on that engine especially if someone has changed a head or a gasket. that being said the compresion is sufficient for combustion. you have an issue with either fuel or more likly ignition.
however as the rig sat idle for 2 years it may have gummed up carbs.

CaptainBruce · Jan 14, 2008

Re: 94 150 XR6 merc won't start?

UPDATE.....
Got it RUNNING ....
You guys were right on....The timing was 180 Degrees off...
Thats what I get for "ASSuming" that the timing would be close..to what it was before I put everything back together.
Thanks to hkeinder ,Rodbolt1.o and All who suggested that I check everything over and over again!
CaptainBruce

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