I recently upgraded boat and motor from my old Javelin with GT 150 to a 92 Ranger with a 92 Johnson Fast Strike J150GLENC. A little back story - bought the boat knowing the tach was bad. Took it out on Friday to run it and get to know it. It had been setting since October (here in kansas) at the dealer so I put some Sea Foam in with Gas. It started but idle was rough and had to throttle up to keep it running. Ran good above idle, jumped on plane great, and top end ran like a dream but anytime I went back to idle it just didn't want to stay running. Bought a tach on Saturday for it and spoke to dealer about idle issue. Dealer gave me a can of BRP decarb cleaner and explained procedure. I installed the tach yesterday morning and did the decarb treatment with the dog ears on in the driveway. I also checked the timing arm and noticed there was a gap which I corrected. I noticed the brand new tach seemed to be acting erratically at first - didn't move off of 0 for the first couple minutes, then seemed to work accurately from there for the most part. The treatment made a big difference by last night and it seemed to idle great. The idle speed sounds better and it didn't act like it was sputtering or near dieing ever.
I've read a bunch on here about tach issues and a possible rectifier / VR issue as a culprit and the dealer had mentioned that if the tach doesn't work right we could be looking at a VR issue. I've got 10 days under warranty so I'm trying to pin point the issue and get it corrected before that time is up and I want to make sure I check the VR. From what I've gathered by reading previous posts is I can use a volt meter to check it. First I need to check the lead at Tach for 9v, then put it on battery and check to see if it's between 12.5 - 14 while running. Any other things to do to check it? I'm going to take it out tomorrow to the lake and see how the idle does "on the water" as well as perform any tests I can to check the VR.
The battery does have SS nuts on it but I will add the washers to it today as well.
Thanks in advance for any advice or help. Sorry for the short novel![]()