Mercruiser 170 HELP

R

Regal4Me

Recruit
Joined
May 31, 2003
Messages
4
I just got this in the water (new me me... 1985 Regal with 170 mercruiser...and need some serious help!<br />(sounds similar to question listed several posta ago requesting merc 470 carb help)<br />Just tuned up (new plugs, wires, cap. rotor, dwell set and carb ... 2 barrel merc..cleaned)<br />Hit forward and did backfires and dies!<br />Engine sticker reads 8degrees BTDC... later service bulletin says ...4 degrees, when I first got this it was at 10 degrees!<br />Any ideas...where to start? Carb or, timing?<br />Anybody with experience with this problem?
 
Bob_VT

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,082
Re: Mercruiser 170 HELP

8 degrees is the correct one as per the manual. Inside the carb there is an accelerator pump and those are prone to wear a bit....it will cause the boat to bog down (almost stop running) before takeoff.<br /><br />A second thought (which happened to my 470/170 last Summer) is to check the fuel pump. My boat would start but never go beyond an idle speed. Check to see is there is gas in the clear plastic line that goes from the fuel pump to the block. If there is gas in there you need a pump. If the pump has failed then this will only allow an idle condition. Be sure to replace with a marine pump (NAPA has them for your motor).<br /><br />Bob
 
Bob_VT

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,082
Re: Mercruiser 170 HELP

8 degrees is the correct one as per the manual. Inside the carb there is an accelerator pump and those are prone to wear a bit....it will cause the boat to bog down (almost stop running) before takeoff.<br /><br />A second thought (which happened to my 470/170 last Summer) is to check the fuel pump. My boat would start but never go beyond an idle speed. Check to see is there is gas in the clear plastic line that goes from the fuel pump to the block. If there is gas in there you need a pump. If the pump has failed then this will only allow an idle condition. Be sure to replace with a marine pump (NAPA has them for your motor).<br /><br />Bob
 
R

Regal4Me

Recruit
Joined
May 31, 2003
Messages
4
Re: Mercruiser 170 HELP

oh, after 20 minutes of stalling... it finally warmed up enough to get it in gear. Engine runs great at WOT with timing at 4 degrees. Seems to bog an die at 8 degrees. I heard that if you put a 1/4 inch ball bearing in the accellrater pump (to reduce the volume.... this helps?)<br /><br />just rebuilt carb but, I didnt swap out accel. pump. <br /><br />what causes that the engine to die when you hit forward gear anyhow?
 
D

DJ

Guest
Re: Mercruiser 170 HELP

Regal,<br /><br />I think Bob answered your question. The accel pump is critical, if you didn't service it, you need to.
 
L

LBL

Recruit
Joined
Jul 5, 2009
Messages
3
Re: Mercruiser 170 HELP

Interesting... I had the same problem with my 170 2bbl and it turned out that the passage between the accelerator pump and the venturi in the throttle body was plugged. Soaked it with carb cleaner for a while and it cleaned it out and runs fine now
 
You must log in or register to reply here.
Top