4.3l l-6 mercury gm motor boat


Old 12-26-02, 08:53 PM
Visiting Guest
Posts: n/a
Unhappy 4.3l l-6 mercury gm motor boat

i have a mercury motor with a gm block 250 cb anyway it had a blown bearing main and rod so i replaced all bearings and gaskets and a piston rod and new crankshaft and harmonic balencer i put it all back to geather and i lined up the timing gear right sow im trying to get it started but it just wont start it wont catch wont spark the plugs i guess or the plugs wont spark the feul or something like that anyway it has a new cap and rotor and new points still wont work its lined up right and i ajusted the rod heads or lifters right also it still wont fire up and run i need help or step by step to gett it runing i bought a book and read it and fallowed instructions to the t and still wont fire desperite need of help if you can that would be great im gonna try to work on it this spring asasp evcen might work on it in the winter if i can get it to a garage to wrok on it
if you can help thanks quick responce repquested
Sponsored Links
Old 01-01-03, 07:28 PM
BoatMech's Avatar
Join Date: Dec 1999
Location: Los angeles
Posts: 592
I and the rest of the moderators are here to assist you in
getting all the info you need.
The manual of course is the right first step.
If you are sure you got the timing marks right when you
slid in the cam then lets take a compression test,
Remember there are three things necessary.
Old 01-02-03, 02:20 AM
Visiting Guest
Posts: n/a
not sure

i know that it is getting spark im pretty sure anyway abd as far as fuel it doesnt seem to be getting fuel from the tank i have been poring fuel into the carb when i was trying to get it started and as far as compression how do i check that if the boat is stationary and ow way to get it to the shope what type of tools do i need thanks
ps what would be wrong that its not getting fuel from the tank or is there something wrong with the carb??
Old 01-09-03, 08:25 PM
BoatMech's Avatar
Join Date: Dec 1999
Location: Los angeles
Posts: 592
Ok lets keep it safe, no more pouring fuel anywhere. thanks.

You can run a compression test by removing the spark plugs
and installing compression gauge. then you simply disconnect
the coil wire and crank the engine over a few times.
Usually five revolutions or watch the needle on the gauge rise
five times. Write me back with the results.
As far as the fuel, you could have put the fuel pump in incorectly.
Or damaged the fuel pump pushrod if it is v6 engine.
You should measure the fuel pump vaccuum.
But we'll get to that later.
Be careful with that gas. Never have open fuel sources
near an engine when you are working on it.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes