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4hp Fuel Pump

rhonsberger

New member
"The plastic mounting bracket

"The plastic mounting bracket that goes between the fuel pump and crank case is breaking on my 4hp Nissan. I was not getting fuel, took the fuel pump off and noticed the plastic collar around the pump rod was cracked. I replaced the pump and the new one was likewise shattered in short order. Any thoughts on what is going on????"
 
Do you mean the plastic body o

Do you mean the plastic body of the fuel pump itself is cracking? That's the piece with the two nipples on it.
 
"I apologize in advance if I&#

"I apologize in advance if I'm using the wrong terms here. The fuel pump is metal, then between it and the crank case is a plastic plate, perhaps 5 mm thick or so. The plastic continues into the mounting hole forming a sleave over the rod that drives the pump. The sleave around the pump is cracking, in fact, being destroyed. Seems like the cam or lifter that drives the rod is out of alignment or otherwise damaged."
 
"Rick,

The fuel pump is the


"Rick,

The fuel pump is the assembly itself including the plastic and metal bits...And I was wrong, the metal piece has the nipples on it.

The plastic mounting secion can't break unless it is being tightened down too much or if you are mounting the pump 90 degrees off. The arrow should be pointing up when you mount it."
 
It is mounted correctly. I re

It is mounted correctly. I replaced the broken pump with a new one and it promptly broke as well. Something internally is broken or out of alignment..
 
"I talked to Tohatsu and asked

"I talked to Tohatsu and asked them what could cause it...They said the same thing, over tightening. The only thing thing that I can think of other than that would be a miss cast block. If the mounting surface was not milled correctly it could stress the plastic. I would call them at 972-323-6003 and ask them where to take it to have it examined. By the way, how old is the engine?"
 
"It's a 2005. It has run

"It's a 2005. It has run fine for 4 years. Started choking out last year, died altogether a few weeks ago. I diagnosed that it was not getting fuel. When I took the fuel pump off I noticed the plastic piece was cracked, in fact a chip was missing from the sleeve portion, presumably in the oil pan. I changed the oil several times trying to flush it out, but saw nothing. I replaced the fuel pump with a new one, and it started right up. It ran for 10 seconds and died. Took the new pump off and it was shattered exactly like the first one. I took it into a local dealer and they have been lying to me, telling me things like it is on the bench now, we'll call you later, and never do. The last was that they have ordered a new fuel pump, in spite of not yet diagnosing the problem, nor giving my a quote. Anyway, it all seems fishy to me and not trusting them wanted a better understanding of what could be wrong."
 
"I think you should call Tohat

"I think you should call Tohatsu and get them involved in the repair process. It's out of warranty, but they still have an interest in the repair process....Especially on such an unusual circumstance."
 
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