1988 Johnson gt 150 v6

isaac75

Recruit
Joined
Jun 16, 2020
Messages
3
motor runs great on the hose but when its on the water it bogs down and won't do over like 10 mph. When the motor is put in reverse it gets this horrible clanking sound im new to this so any advise helps thank you
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,884
I believe it just sounds great to you on the hose.-----They will all " bark and roar " even running on 3 of 6 cylinders.-----Start with a compression test.---Post the numbers.-----Then see if spark will jump a gap of 3/8" or more on all leads.
 

isaac75

Recruit
Joined
Jun 16, 2020
Messages
3
Engine compression test done 6/19/2020
2- 55 psi
4- 60 psi
6- 55 psi
1- 55 psi
3- 0 psi
5- 0 psi
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,884
Remove cylinder heads for inspection.-----This is beginning to look like an overhaul is needed.-----Big $$$ may be needed to fix this.
 
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