Possible oil leak near fuel pump bolt

[karayj]

I have an 89 MerCruiser 3.7 that sat for a long time I’ve put quite a few posts up here to bring them back to life. So I decided to change the fuel pump thinking that diaphragm is got to be worn out why not. Well when I was installing the new one obviously.
I had tighten the bolts and when I went to tighten the left side I felt that she started to spin and I stopped immediately it was snug and I said oh boy let’s not spin this bolt. I have a few more weekends of summer to go and it’s been holding up but it’s going to be something I need to face. What is the best way to handle a stripped bolt by the fuel pump.

One thought was like we all do just go one size larger but I’m concerned about the threads and the shavings and all that stuff going into the crank case. My other thought was and I forget the name of that system where you drill it out you tap in a thread but once again my concern is metal bits going into the crank case when I go to drill it out. I will say this I am shocked that it was spinning I mean I’m the second owner of this boat prior to me the guy took it to the dealership all the timeI’m going to be winterizing it in about two weeks after I do that this is when I plan on attacking this or maybe next spring

 

[Rick Stephens]

First you must pull the bolt out and inspect it. No way to tell from here what the damage is.

 

[karayj]

I’m definitely gonna do that but I’m just trying to figure out what way is best to fix the issue that’s all I want to be aware of when I’m tapping and drilling in that area

 

[RaceCarRich]

Maybe you’ll be lucky and you stripped the bolt and not the hole.

The kit you are referring to is Heli-Coil.

 

[karayj]

You know one thing I forgot to mention in my post is when I replace the Fuel pump there was a very thick what I thought was some sort of spacer gasket no maybe I don't need this and that's why the bolt is spinning because it's too short is it normal to have at least 1/4 inch thick gasket and when I bought fuel pump it came with three gaskets thin ones.

My question is what's the deal with the spacer and is it really needed I know that a shaft comes down and hits the fuel pump that's connected to the Cam and if it's too close I could cause bigger problems so I'm a little confused is this spacer normal for an 89 3.7 mercruiser I will add pics later

 

[Rick Stephens]

Some pumps require spacers for a given application. Some pumps may fit more than one engine block by virtue of the spacer. You can confirm the fit with some measurements of the rod, or pump arm if that is the case, when the motor is turned over. Have to be careful deleting the spacer as the pump diaphragm can be damaged if the spacer is needed. However, the '89 3.7 Mercruiser parts list for the *OEM pump* only shows a gasket.

 

[nola mike]

The spacer is to regulate the fuel pressure. I'd stick with the same width that's in there. If you leave it out, your fuel pressure will be too high.

 

[Rick Stephens]

The spacer is to regulate the fuel pressure. I'd stick with the same width that's in there. If you leave it out, your fuel pressure will be too high.

Din know that. Might just get away with longer bolts.

 

[karayj]

I will keep the spacer since the old pump had one and keep one inner and one outer gasket . Right now there is a very very minor sweat of oil. I will winterize it and deal with this in April,

 

[Scott Danforth]

its an aluminum block. pull the pump, install a helicoil kit and go boating.

on your new to you boat, with the new to you platypus motor (the infamous 470).......

make sure to inspect the exhaust elbow and joint for corrosion
make sure you clean the HX
verify you have the updated HX
make sure you check the cam snout seal and water circulating pump
pressure check the cooling water
make sure you change the raw water pump (whole kit including the housing)
do the drive service
inspect the U-joints - replace as needed
inspect the gimbal - replace as needed
check the alignment
replace the bellows
change engine oil and filter
clean the fuel system from the tank to the carb (pickup filter, AS valve, fuel filter, pre-filter on carb and go thru the carb)
replace points, condenser, cap, rotor, wires and plugs. then properly file the points, gap them, verify dwell, set timing

then move on to the trailer
service the brakes, bearings and coupler
service any bunks/rollers/guides
inspect the welds, paint, etc.
replace the winch rope
check the tire

 

[karayj]

WOW Thank you all that info... I did about 90 % of that in the last few months for precaution and now that I see your post I did it right ..This forum has been so helpful. > I will read up on how to Helix a bolt. My concern is how did this happen? who F'ed it up before me, I am the 2nd owner and it was dealer maintained.

 

[karayj]

Hey Rick Stephens is there a way of telling me what the Bolt size is #21 so i know what kit to buy?.. How does the kit work?
I assume you buy a kit that is 1 size larger? bolt wise Nm I found it Bolt (.312-18 x 1.375)

 

[todhunter]

It's more expensive than Heli-Coil, but I far and above prefer a Time-Sert repair. For heli-coil and Time-Sert, you buy the kit that is the SAME SIZE as the hole that is stripped. The kit should come with all you need to drill out the bad threads, tap for the insert, and install the insert. I would definitely recommend using a Heli-Coil over just up-sizing the threads in the block. Typically the next size up would not give you full thread engagement, meaning it will be weak and likely to strip as well. Good luck.

 

[kenny nunez]

The bolt is a 5/16” X 18 threads per inch. NAPA sells Helocoil kits, Sometimes the Helicoil tap will start in the the stripped threads without drilling since you are working with aluminum. The main thing is keeping the tap straight. I am pretty sure that the threads go clear through the engine block. So you have to be careful not to run the Helicoil all the way into the crankcase. The driver tang on the leading edge of the Helicoil might be not deep enough and the bolt for the fuel pump might bottom out against it. You will have to do a trial fit turning the bolt by hand to feel if that is happening.

 

[todhunter]

I am pretty sure that the threads go clear through the engine block. So you have to be careful not to run the Helicoil all the way into the crankcase. The driver tang on the leading edge of the Helicoil might be not deep enough and the bolt for the fuel pump might bottom out against it. You will have to do a trial fit turning the bolt by hand to feel if that is happening.

Another reason I'm a fan of Time-Serts - they don't have the tang at the bottom of the hole. Instead they have a shoulder at the top of the hole to control insertion depth, so thru-holes are not an issue (other than making sure you don't put chips into the crankcase). Most folks balk at the ~$100 price tag, though.

 

[Grub54891]

With the flange on top, wont that interfere with the gasket? Its supposed to be flush with the surface.

 

[Scott Danforth]

with the fuel pump out
shove a rag in the hole - that will keep chips from dropping into the pan
grease the helicoil tap (to catch the chips)
tap the hole
take helicoil and insertion tool, slather with blue loc-tite.
install
wait 3 minutes
install pump and bolts
go boating

while I agree, Thread-serts and Time-serts are a slightly superior method to thread repair, its like hitting a 10d nail with a 5# sledge hammer in this case. Helicoil is perfectly adequate.

 

[todhunter]

With the flange on top, wont that interfere with the gasket? Its supposed to be flush with the surface.

No, the kit comes with a piloted countersink - the flange of the insert sits below the mating surface.

 

[Grub54891]

No, the kit comes with a piloted countersink - the flange of the insert sits below the mating surface.

Thank you. I'll have to check them out next time I need one.