'86 mercruiser 170 has spark no start!

Cynicaltrip · Aug 6, 2012

Hi guys im back again!..lol this time i fixed the spark issue with a new cap and rotor....have spark to plugs now...cranked motor several times no start, not even a hint of wanting to...pulled flame arrestor off looked into carb noticed fuel pooled up down in intake manifold...little back story to motor is everything has been redone...was stripped to block and sent to machine shop then was reassembled with all new parts..i didnt rebuild carb...was having spark issue with no spark to plugs but have fixed that..why is it pooling in intake manifold?..and why wouldnt it atleast wanna try and fire before flooding? motor is set at 6 degrees btdc has Hotspark ignition module in it..was hoping when i fixed the spark issue it would fire lol...havent ever been on the water yet since i bought the boat last year...so i never have heard the motor run... boat sat for 2 years before i bought it..any info or ideas would be greatly appreciated guys thanks!

Bt Doctur · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

what motor are you calling the "170"
timing and firing order correct
valves adjusted too tight
how did you set the timing
what is a hot spark
you never heard it run but rebuilt the engine because you didnt have spark???????????????????????

Cynicaltrip · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

3.7 mercruiser .....and the owner before seized the motor so I had a. .30 over kit put in...hotspark is the name of the company that makes the electronic ignition module..

Cynicaltrip · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

Timing is at 6 btdc and as far as I know the firing order is set right. Was wandering if dizzy is out 180 degrees wouldn't it still spit or sputter...and as far as valve adjustments it was set to spec in manual..

Bt Doctur · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

the pushrods in the 3.7 are very specific because thare is no adjustment using the rocker nuts.valve lash is checked and the correct oversize push rods are installed. firing order is 1,3,4,2 cylinder numbered 1,2,3,4 front to rear.

Cynicaltrip · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

Yes that's the correct firing order that it was set to...as far as push rods it was all assembled using the rebuild kit from falcon...was complete motor rebuild kit...would a compression test eliminate doubt about valving issues?

Bt Doctur · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

did you specify the proper lenght of the pushrods? compression test will tell the whole story.

Cynicaltrip · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

No I did not specify length when ordered..the machinist ordered the kit so I assumed....I guess ill do a compression test that will tell me if I should dig deeper and check rod length I assume?...thanks for the good info doc!

Bt Doctur · Aug 6, 2012

Re: '86 mercruiser 170 has spark no start!

quickie test for compression is put your hand over the carb and crank the engine, cant suck fuel into a cylinder if theres no sucking.

Cynicaltrip · Aug 7, 2012

Re: '86 mercruiser 170 has spark no start!

Sounds like a plan...ill check it after work today doc and let you know!

Cynicaltrip · Aug 7, 2012

Re: '86 mercruiser 170 has spark no start!

K update time....checked compression was great....put hand over carb and it had suction while cranking....rechecked spark and its very weak at plugs...new cap and rotor just put on....I bought new plug wires few months back and they were never suspect until now....could they not work with my ignition system...plugs are msd streetfire 8mm.....could they maybe not carry enough current to plugs?...if not what plug wires does anyone suggest for this motor with electronic ignition?..

Bt Doctur · Aug 7, 2012

Re: '86 mercruiser 170 has spark no start!

verify that you are on #1 compression stroke, TDC and rotor is pointing at the plug wire going to #1 plug.

Cynicaltrip · Aug 13, 2012

Re: '86 mercruiser 170 has spark no start!

K another update....has great spark at coil wire....timing is set correctly on compression stroke to 6 degree btdc....has great compression...seems like when I put the coil wire back onto cap I get nothing to weak spark at the plugs....nowhere near the spark I see at coil wire..why or how am I losing the spark?...I tried adjusting the magnets position on dizzy cam that didn't seem to do anything and I tried advancing and retarding the dizzy to try and catch the spark still nothing...only thing logical that I can think of left to try is awhile back when motor was apart I took apart the dizzy to clean it...maybe its not put back together correctly lol Idk grasping at straws now!....plz help!

Cynicaltrip · Aug 13, 2012

Re: '86 mercruiser 170 has spark no start!

Any suggestions?.....

'86 mercruiser 170 has spark no start!

Cadet

Supreme Mariner

Cadet

Cadet

Supreme Mariner

Cadet

Supreme Mariner

Cadet

Supreme Mariner

Cadet

Cadet

Supreme Mariner

Cadet

Cadet