General Electric stock has shot up over 50 percent in the last three months but that comeback "has gone way too far," J.P. Morgan analyst Stephen Tusa told CNBC on Wednesday.

"At this stage of the game, the math is the math," Tusa said on "Squawk on the Street."

"Earnings are too high, estimate-wise from a consensus perspective, and cash is way too low," Tusa added.

Tusa has a $6 price target on GE's stock. GE shares opened trading Wednesday up 1.2 percent at $10.83 a share.

The analyst gained a following on Wall Street for his work on GE after his negative call in May 2016. Tusa was the first to warn investors that shares of the one-time Dow Jones Industrial Average member were going to fall, back when the stock was above $30.

GE's stock jumped on the day in December that J.P. Morgan upgraded the company's rating to neutral from underperform.

Tusa was critical of the idea that GE's stock should rise because of CEO Larry Culp providing more insight to the company's business.

"You don't just get an entitlement for saying 'we're going to call it what it is and we're going to operate above board,'" Tusa said.

However, Tusa praised Culp as a leader, saying his J.P. Morgan team loves the GE CEO.

"I think Larry is a phenomenal CEO. I have a personal affection for him. He's a fantastic guy," Tusa said. "I know he's a credible person and they weren't going to sit there and do nothing, so our view there was that they could come out and do some things and people would, you know buy into it, believe it and the stock would move up from there based on the narrative and sentiment."

Tusa also defended why J.P. Morgan's stock target for GE remains well below Wall Street's consensus, as well as why he is still looking for more evidence of a true turnaround.

"We never said the stock was going to go to zero," Tusa added. "I think that was always kind of a straw man bear case that the bulls put out there to say, 'Hey it's not as bad as Tusa thinks' or whatever."