Fuel Gauge Problem - Sender Unit on 2002 Fisherman

MT Bob

Cadet
Joined
Jul 15, 2007
Messages
17
Some of you may be interested in a problem I've had with a fuel sending unit on my 1700 Fisherman. Recently I added two cans (32 oz) of Sea Foam to my 26 gal gas tank (2002, Lund 1700), in an effort to help a carburetor problem - per recommendation of a number of Merc. outboard repairmen, and the local Lund dealer.

With a full tank of gas, I took the boat out two days ago and discovered that the fuel gauge read empty. I pulled the floor board and found the tank was full. I pulled the sender (WEMA model UFW 5.5, manuf date 3/13/02) and found that by manually moving the float, the sender was working OK. I then did a series of tests on the float with pure gas, gas diluted with Sea Foam and straight Sea Foam. I think that the Sea Foam lowered the specific gravity of the gasoline and the float was not able to displace its own weight with that additive in the gasoline. The result was that the sender's float apparently sank in the gasoline with Sea Foam added. Evidently this is caused by the plastic material will not floating correctly with a Sea Foam additive.

So, I've decided to purchase a replacement sending unit from WEMA that uses a stainless steel float. I've not received the new float yet, but will follow-up with a post when I get it installed. Hopefully the stainless float will not sink in the gasoline with Sea Foam additive. By the way - WEMA USA is the manufacturer of the sending unit and they have been great to work with, nice folks, good service.
 

Barnacle_Bill

Admiral
Joined
Feb 8, 2004
Messages
6,469
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

You just have a defective float. It wasn't the Sea Foam.
 

MT Bob

Cadet
Joined
Jul 15, 2007
Messages
17
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

You just have a defective float. It wasn't the Sea Foam.
That's what I thought until I talked to the float manufacturer, WEMA. The float is actually made of a solid plastic material. There is no cavity in the float. It appears that the solid plastic design is only slightly lighter than gasoline and, when Sea Foam is added, the specific gravity of the gasoline changes and the float sinks.
I have now received a stainless steel model from WEMA (stainless body and float) and installed it. It works great.
 

greenbush future

Lieutenant Commander
Joined
Aug 28, 2009
Messages
1,814
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

That's what I thought until I talked to the float manufacturer, WEMA. The float is actually made of a solid plastic material. There is no cavity in the float. It appears that the solid plastic design is only slightly lighter than gasoline and, when Sea Foam is added, the specific gravity of the gasoline changes and the float sinks.
I have now received a stainless steel model from WEMA (stainless body and float) and installed it. It works great.

I need to replace my sending unit on my Tyee, 96 what did you have to pay for the new one?
Thanks Dan
 

MT Bob

Cadet
Joined
Jul 15, 2007
Messages
17
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

I need to replace my sending unit on my Tyee, 96 what did you have to pay for the new one?
Thanks Dan

Sorry for the delay - I paid $68 incl shipping for model No. SSS-5.5S
This model has a stainless steel body, shaft and float.
 

jpbohney

Cadet
Joined
Jul 12, 2003
Messages
8
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

I have a 2003 lund fisherman 1800. Where is the sending unit? What floorboard needs to be removed to find it? thanks
 

Billfo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
189
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

:D Very glad I just read your post. I just had a fuel leak around the sender (bad gasket).(2000 Adventure 1800). When I reinstalled my float level device, now that you mentioned it, my float SANK... Didnt really think about it at the time as the fuel gauge worked fine a few days before.. ! However never the less, I did see the float sink ! yes, I added Seaform for the first time this fall..

I may as well replace it before I reinstall the floor.. Thanks, Bill


Some of you may be interested in a problem I've had with a fuel sending unit on my 1700 Fisherman. Recently I added two cans (32 oz) of Sea Foam to my 26 gal gas tank (2002, Lund 1700), in an effort to help a carburetor problem - per recommendation of a number of Merc. outboard repairmen, and the local Lund dealer.

With a full tank of gas, I took the boat out two days ago and discovered that the fuel gauge read empty. I pulled the floor board and found the tank was full. I pulled the sender (WEMA model UFW 5.5, manuf date 3/13/02) and found that by manually moving the float, the sender was working OK. I then did a series of tests on the float with pure gas, gas diluted with Sea Foam and straight Sea Foam. I think that the Sea Foam lowered the specific gravity of the gasoline and the float was not able to displace its own weight with that additive in the gasoline. The result was that the sender's float apparently sank in the gasoline with Sea Foam added. Evidently this is caused by the plastic material will not floating correctly with a Sea Foam additive.

So, I've decided to purchase a replacement sending unit from WEMA that uses a stainless steel float. I've not received the new float yet, but will follow-up with a post when I get it installed. Hopefully the stainless float will not sink in the gasoline with Sea Foam additive. By the way - WEMA USA is the manufacturer of the sending unit and they have been great to work with, nice folks, good service.
 

Billfo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
189
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

On my 2000 (1800) the tank is under the center section of the floor. The 2' x 6' section with about 16 screws.

9520_1264604859365_1357051056_30782611_5151953_n.jpg


I have a 2003 lund fisherman 1800. Where is the sending unit? What floorboard needs to be removed to find it? thanks
 
Joined
Nov 8, 2010
Messages
1
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

Would it be cheaper to just quit using seafoam and use another product in your fuel. What are you using the seafoam for ??
 

DonHof

Petty Officer 1st Class
Joined
Oct 19, 2009
Messages
318
Re: Fuel Gauge Problem - Sender Unit on 2002 Fisherman

Had the same problem with my 6.6 gallon tank. Gauge would work great
put some sta-bil in and the float would start to sink. The sta-bil would
attach itself to the float and make it heavy. Got rid of the sta-bil
and went with crc and mixed it very good.
 
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