Trying to get a Merc 135 hp V6 back in shape

[Scand]

Hi

Trying to get some help getting a 1988 Merc V6 135 hp back in shape to my son?s speed boat. This question is from Sweden.

The first issue of this motor is the oil injection. It?s a lottery. The horn may sound or be silent when turning the key. If it sounds, it may be beep-beep-beep-beep or continuously beep-beep-beep-beep-beep-and so on. It may also be a constant beeeeeeeeeeeeeep like overheating. Temp is OK, motor runs OK with a slight bluish smoke. The motor does not have a oil tank, just the oil reservoir. We have been running the motor with a rigged sensor in the reservoir lid to prevent it from beeping and just filling/monitoring the reservoir. The beeping is really annoying. I consider removing the oil injection or disconnecting the horn and install a light signal instead. -What is your opinion? I would not like to pay for a full service as this will be more costly than the motor itself...in Sweden marine things are at least twice as expensive as in northern America.

The second issue is the serial number. The only thing I found was a stamped number in a freeze plug on top of the engine. B349117 implies that it is indeed a V6 135 hp from 1988, but since I haven?t found anything on the internet of this location of serial number, I am not sure. -Is this the correct serial number?

The third issue is that the vertical fin is damaged, some 1-1,5 inch is missing. -Do I dare to weld repair this (TIG) without the risk of distorting the shape of the lower gear housing? Is there any other way to fix this?

I have changed impeller, gear oil and spark plugs. Next stop thermostats.

The motor runs great, strong and stabile on idle rev.

Hoping for your help, regards

Hansen, Sweden

 

[carholme]

Re: Trying to get a Merc 135 hp V6 back in shape

Your s/n comes up as:

MERCURY - (135 H.P. (1988 ))
Serial No: 0B349117 Model No: 1135412BD

Parts and Service Bulletin List for s/n 0B349117:

Search Results - Crowley Marine

The skeg can be welded but what I have done with several engines is to build up the missing piece with JB Weld and sand it down to match a new profile. It will break if it something hits the skeg but it acts as a sacrificial item and usually prevents damage to the remainder of the original piece.

Gerry

 

[DrMattB]

Re: Trying to get a Merc 135 hp V6 back in shape

I have the same engine on my 19 ft Mako. The oil alarm went off intermittently, so I went through all the diagnostic tests on the oil injection, and found it was not working properly. It was very simple to bypass it, and only took about 1 hour. Disconnect the oil line where it "T's" into the gas line, then reconnect the gas line as a straight connection. Take the outgoing oil line that used to be "T" to the gas line and "T" that to the incoming line to the undercowl oil tank. You have basically set up a recirculating pump for the oil. It keeps all the components in place, so it can easily be reconnected if you want to repair the oil pump. It is also a lot less work than removing the whole system. Then trace the wire from the alarm sensor box (just to the rear of the pump) to the wire connection on the opposite side of the engine and disconnect it (if I remember correctly, it is beige with a blue stripe). This turns off the beeping for the oil alarm, but leaves your overheat alarm operational. Then premix your fuel with 50:1 oil, and you don't have to worry anymore.

Matt

 

[Scand]

Re: Trying to get a Merc 135 hp V6 back in shape

Thanks a lot guys!

I will follow the advice on the skeg. I will drill and thread a number of holes and use some stainless screws without heads to act as inforcement in the JB Weld to make the repair stronger.

I didn?t realize that I could simply make a loop of the oil system and keep the system on the motor. Excellent. I was worried about the plastic axle and the bushing inside. I was also not sure about the overheating alarm and if it still would be in operation after removing the oil injection system.

An old Mercury is saved for the afterworld. I will probably disconnect the oil pump at once down in the harbour, I have a lot of premixed gas which I need to consume before winterizing the boat.

A very grateful Swede.

Regards/Hansen