older 70's mercury 135hp 2stroke inline 6, not running worth a crap

[azboating]

Hi,
new here but, having some issues.

my boat is a newer 2000 Hurricane 17' (not that it matters), the motor is a 1970's 135hp mercury inline 6 2stroke. when i start it, it runs fine in nuetral, revs up good, etc... but as soon as i put it in gear, it bogs out and dies, or just dies (sometimes i don't even get to give it throttle before it dies)

i have no history on the motor, the prop is a 2blade "speed prop" of some sort, has new plugs (didn't help any), gas is mixed 50:1.

sometimes if you accelerate slowly, you can get it to go a little bit (maybe hitting..25-30knots?) but, still far below what this motor SHOULD be putting the boat at. and we only got it to do that twice, then after running half way across the lake (1mile?), it died out and stalled.

any input?
motor LOOKS like this one, but this isn't mine:

 

[azboating]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

well i've figured out this is a 1971 thunderbolt 1350. beyond that i've come up with little info...anyone know of a free online resource to get tuneup specs, and the proper ways of adjusting the timing, and carbs?

 

[kingsnakejr]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

AZ,
Don't know of a free online source but what I did was go to Ebay and look for a repair manual for my outboard. Got one for about $10 and it has everything from tune-up to complete overhaul. Got the one on CD not an actual manual. Easier to reference and won't get greasy. I feel confident about any repair job on my outboard. Hope this helps.

 

[Chris1956]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

I recommend you start with the basics. Do a compression check and assure all cylinders as 100+PSI and even. Next put a timing light on each plug wire and mae sure you have spark to each plug. If so, now employ Clam's link ans sync procedure to make sure the spark timing is good. If it still runs like crap (it likely will) clean and rebuild the carbs.

 

[azboating]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

I recommend you start with the basics. Do a compression check and assure all cylinders as 100+PSI and even. Next put a timing light on each plug wire and mae sure you have spark to each plug. If so, now employ Clam's link ans sync procedure to make sure the spark timing is good. If it still runs like crap (it likely will) clean and rebuild the carbs.

what is clam's link & sync procedure?

 

[azboating]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

ello?

 

[imported_Voyager]

Re: older 70's mercury 135hp 2stroke inline 6, not running worth a crap

This is the link/synch post: http://forums.iboats.com/showthread.php?t=128495&highlight=link+synch

As Chris says, do the basics, then set timing as per the link/synch post. If you have spark, compression and the timing is right, there is a fuel issue; Rebuild the carbs.

Don't keep trying to run the motor until you find the root cause, if two cylinders aren't getting fuel (which could cause your symptom) they aren't getting lubrication either.